introduction to computer problem solving notes

THE PATH TO SUCCESS IN EXAM...

Introduction to Problem Solving – Notes

Introduction to problem solving.

Steps for problem solving ( analysing the problem, developing an algorithm, coding, testing and debugging).
flow chart and
pseudo code,

Decomposition

Introduction

Computers is machine that not only use to develop the software. It is also used for solving various day-to-day problems.

Computers cannot solve a problem by themselves. It solve the problem on basic of the step-by-step instructions given by us.

Thus, the success of a computer in solving a problem depends on how correctly and precisely we –

Identifying (define) the problem
Designing & developing an algorithm and
Implementing the algorithm (solution) do develop a program using any programming language.

Thus problem solving is an essential skill that a computer science student should know.

Steps for Problem Solving-

1. Analysing the problem

Analysing the problems means understand a problem clearly before we begin to find the solution for it. Analysing a problem helps to figure out what are the inputs that our program should accept and the outputs that it should produce.

2. Developing an Algorithm

It is essential to device a solution before writing a program code for a given problem. The solution is represented in natural language and is called an algorithm.

Algorithm: A set of exact steps which when followed, solve the problem or accomplish the required task.

Coding is the process of converting the algorithm into the program which can be understood by the computer to generate the desired solution.

You can use any high level programming languages for writing a program.

4. Testing and Debugging

The program created should be tested on various parameters.

The program should meet the requirements of the user.
It must respond within the expected time.
It should generate correct output for all possible inputs.
In the presence of syntactical errors, no output will be obtained.
In case the output generated is incorrect, then the program should be checked for logical errors, if any.

Software Testing methods are

unit or component testing,
integration testing,
system testing, and
acceptance testing

Debugging – The errors or defects found in the testing phases are debugged or rectified and the program is again tested. This continues till all the errors are removed from the program.

Algorithm is a set of sequence which followed to solve a problem.

Algorithm for an activity ‘riding a bicycle’: 1) remove the bicycle from the stand, 2) sit on the seat of the bicycle, 3) start peddling, 4) use breaks whenever needed and 5) stop on reaching the destination.

Algorithm for Computing GCD of two numbers:

Step 1: Find the numbers (divisors) which can divide the given numbers.

Step 2: Then find the largest common number from these two lists.

A finite sequence of steps required to get the desired output is called an algorithm. Algorithm has a definite beginning and a definite end, and consists of a finite number of steps.

Characteristics of a good algorithm

Precision — the steps are precisely stated or defined.
Uniqueness — results of each step are uniquely defined and only depend on the input and the result of the preceding steps.
Finiteness — the algorithm always stops after a finite number of steps.
Input — the algorithm receives some input.
Output — the algorithm produces some output.

While writing an algorithm, it is required to clearly identify the following:

The input to be taken from the user.
Processing or computation to be performed to get the desired result.
The output desired by the user.

Representation of Algorithms

There are two common methods of representing an algorithm —

Flowchart — Visual Representation of Algorithms

A flowchart is a visual representation of an algorithm. A flowchart is a diagram made up of boxes, diamonds and other shapes, connected by arrows. Each shape represents a step of the solution process and the arrow represents the order or link among the steps. There are standardised symbols to draw flowcharts.

Start/End – Also called “Terminator” symbol. It indicates where the flow starts and ends.

Process – Also called “Action Symbol,” it represents a process, action, or a single step. Decision – A decision or branching point, usually a yes/no or true/ false question is asked, and based on the answer, the path gets split into two branches.

Input / Output – Also called data symbol, this parallelogram shape is used to input or output data.

Arrow – Connector to show order of flow between shapes.

Question: Write an algorithm to find the square of a number. Algorithm to find square of a number. Step 1: Input a number and store it to num Step 2: Compute num * num and store it in square Step 3: Print square

The algorithm to find square of a number can be represented pictorially using flowchart

introduction to computer problem solving notes

A pseudocode (pronounced Soo-doh-kohd) is another way of representing an algorithm. It is considered as a non-formal language that helps programmers to write algorithm. It is a detailed description of instructions that a computer must follow in a particular order.

It is intended for human reading and cannot be executed directly by the computer.
No specific standard for writing a pseudocode exists.
The word “pseudo” means “not real,” so “pseudocode” means “not real code”.

Keywords are used in pseudocode:

Question : Write an algorithm to calculate area and perimeter of a rectangle, using both pseudocode and flowchart.

Pseudocode for calculating area and perimeter of a rectangle.

INPUT length INPUT breadth COMPUTE Area = length * breadth PRINT Area COMPUTE Perim = 2 * (length + breadth) PRINT Perim The flowchart for this algorithm

Benefits of Pseudocode

A pseudocode of a program helps in representing the basic functionality of the intended program.
By writing the code first in a human readable language, the programmer safeguards against leaving out any important step.
For non-programmers, actual programs are difficult to read and understand, but pseudocode helps them to review the steps to confirm that the proposed implementation is going to achieve the desire output.

Flow of Control :

The flow of control depicts the flow of process as represented in the flow chart. The process can flow in

In a sequence steps of algorithms (i.e. statements) are executed one after the other.

In a selection, steps of algorithm is depend upon the conditions i.e. any one of the alternatives statement is selected based on the outcome of a condition.

Conditionals are used to check possibilities. The program checks one or more conditions and perform operations (sequence of actions) depending on true or false value of the condition.

Conditionals are written in the algorithm as follows: If is true then steps to be taken when the condition is true/fulfilled otherwise steps to be taken when the condition is false/not fulfilled

Question : Write an algorithm to check whether a number is odd or even. • Input: Any number • Process: Check whether the number is even or not • Output: Message “Even” or “Odd” Pseudocode of the algorithm can be written as follows: PRINT “Enter the Number” INPUT number IF number MOD 2 == 0 THEN PRINT “Number is Even” ELSE PRINT “Number is Odd”

The flowchart representation of the algorithm

Repetitions are used, when we want to do something repeatedly, for a given number of times.

Question : Write pseudocode and draw flowchart to accept numbers till the user enters 0 and then find their average. Pseudocode is as follows:

Step 1: Set count = 0, sum = 0 Step 2: Input num Step 3: While num is not equal to 0, repeat Steps 4 to 6 Step 4: sum = sum + num Step 5: count = count + 1 Step 6: Input num Step 7: Compute average = sum/count Step 8: Print average The flowchart representation is

Once an algorithm is finalised, it should be coded in a high-level programming language as selected by the programmer. The ordered set of instructions are written in that programming language by following its syntax.

The syntax is the set of rules or grammar that governs the formulation of the statements in the language, such as spelling, order of words, punctuation, etc.

Source Code: A program written in a high-level language is called source code.

We need to translate the source code into machine language using a compiler or an interpreter so that it can be understood by the computer.

Decomposition is a process to ‘decompose’ or break down a complex problem into smaller subproblems. It is helpful when we have to solve any big or complex problem.

Breaking down a complex problem into sub problems also means that each subproblem can be examined in detail.
Each subproblem can be solved independently and by different persons (or teams).
Having different teams working on different sub-problems can also be advantageous because specific sub-problems can be assigned to teams who are experts in solving such problems.

Once the individual sub-problems are solved, it is necessary to test them for their correctness and integrate them to get the complete solution.

Computer Science Answer Key Term 2 Board Examination

Input Output in Python

Society, Law, and Ethics: Societal Impacts – Notes

Data structure: stacks – notes.

Class 12 computer science Python revision tour - I

Python Revision Tour I : Basics of Python – Notes

Introduction to Python Module – Notes

Sorting Techniques in Python – Notes

Dictionary handling in python – notes, tuples manipulation in python notes, list manipulation – notes, leave a comment cancel reply.

You must be logged in to post a comment.

You cannot copy content of this page

Introduction to Problem Solving Class 11 Notes | CBSE Computer Science

Latest Problem Solving Class 11 Notes includes Problem Solving, steps, algorithm and its need, flow chart, pseudo code with lots of examples.

1 What is Problem Solving?
2 Steps for problem solving
3 What is Algorithm?
4 Why do we need Algorithm?
5.1 Flow chart
5.2 Flow Chart Examples
5.3 Pseudo code
5.4 Pseudo Code Example
6.1 Selection
6.2 Algorithm, Pseudocode, Flowchart with Selection ( Using if ) Examples
6.3 Repetition
6.4 Algorithm, Pseudocode, Flowchart with Repetition ( Loop ) Examples
7 Decomposition

What is Problem Solving?

Problem solving is the process of identifying a problem, analyze the problem, developing an algorithm for the identified problem and finally implementing the algorithm to develop program.

Steps for problem solving

There are 4 basic steps involved in problem solving

Analyze the problem

Developing an algorithm
Testing and debugging

Analyzing the problem is basically understanding a problem very clearly before finding its solution. Analyzing a problem involves

List the principal components of the problem
List the core functionality of the problem
Figure out inputs to be accepted and output to be produced

Developing an Algorithm

A set of precise and sequential steps written to solve a problem
The algorithm can be written in natural language
There can be more than one algorithm for a problem among which we can select the most suitable solution.

Algorithm written in natural language is not understood by computer and hence it has to be converted in machine language. And to do so program based on that algorithm is written using high level programming language for the computer to get the desired solution.

Testing and Debugging

After writing program it has to be tested on various parameters to ensure that program is producing correct output within expected time and meeting the user requirement.

There are many standard software testing methods used in IT industry such as

Component testing
Integration testing
System testing
Acceptance testing

What is Algorithm?

A set of precise, finite and sequential set of steps written to solve a problem and get the desired output.
Algorithm has definite beginning and definite end.
It lead to desired result in finite amount of time of followed correctly.

Why do we need Algorithm?

Algorithm helps programmer to visualize the instructions to be written clearly.
Algorithm enhances the reliability, accuracy and efficiency of obtaining solution.
Algorithm is the easiest way to describe problem without going into too much details.
Algorithm lets programmer understand flow of problem concisely.

Characteristics of a good algorithm

Precision — the steps are precisely stated or defined.
Uniqueness — results of each step are uniquely defined and only depend on the input and the result of the preceding steps.
Finiteness — the algorithm always stops after a finite number of steps.
Input — the algorithm receives some input.
Output — the algorithm produces some output.

What are the points that should be clearly identified while writing Algorithm?

The input to be taken from the user
Processing or computation to be performed to get the desired result
The output desired by the user

Representation of Algorithm

An algorithm can be represented in two ways:

Pseudo code

Flow chart is visual representation of an algorithm.
It’s a diagram made up of boxes, diamonds and other shapes, connected by arrows.
Each step represents a step of solution process.
Arrows in the follow chart represents the flow and link among the steps.

Flow Chart Examples

Example 1: Write an algorithm to divide a number by another and display the quotient.

Input: Two Numbers to be divided Process: Divide number1 by number2 to get the quotient Output: Quotient of division

Step 1: Input a two numbers and store them in num1 and num2 Step 2: Compute num1/num2 and store its quotient in num3 Step 3: Print num3

Pseudo code means ‘not real code’.
A pseudo code is another way to represent an algorithm. It is an informal language used by programmer to write algorithms.
It does not require strict syntax and technological support.
It is a detailed description of what algorithm would do.
It is intended for human reading and cannot be executed directly by computer.
There is no specific standard for writing a pseudo code exists.

Keywords used in writing pseudo code

Pseudo Code Example

Example: write an algorithm to display the square of a given number.

Input, Process and Output Identification

Input: Number whose square is required Process: Multiply the number by itself to get its square Output: Square of the number

Step 1: Input a number and store it to num. Step 2: Compute num * num and store it in square. Step 3: Print square.

INPUT num COMPUTE square = num*num PRINT square

Example: Write an algorithm to calculate area and perimeter of a rectangle, using both pseudo code and flowchart.

INPUT L INPUT B COMPUTER Area = L * B PRINT Area COMPUTE Perimeter = 2 * ( L + B ) PRINT Perimeter

Flow of Control

An algorithm is considered as finite set of steps that are executed in a sequence. But sometimes the algorithm may require executing some steps conditionally or repeatedly. In such situations algorithm can be written using

Selection in algorithm refers to Conditionals which means performing operations (sequence of steps) depending on True or False value of given conditions. Conditionals are written in the algorithm as follows:

If <condition> then Steps to be taken when condition is true Otherwise Steps to be taken when condition is false

Algorithm, Pseudocode, Flowchart with Selection ( Using if ) Examples

Example: write an algorithm, pseudocode and flowchart to display larger between two numbers

INPUT: Two numbers to be compared PROCESS: compare two numbers and depending upon True and False value of comparison display result OUTPUT: display larger no

STEP1: read two numbers in num1, num2 STEP 2: if num1 > num2 then STEP 3: display num1 STEP 4: else STEP 5: display num2

INPUT num1 , num2 IF num1 > num2 THEN PRINT “num1 is largest” ELSE PRINT “num2 is largest” ENDIF

Example: write pseudocode and flowchart to display largest among three numbers

INPUT: Three numbers to be compared PROCESS: compare three numbers and depending upon True and False value of comparison display result OUTPUT: display largest number

INPUT num1, num2, num3 PRINT “Enter three numbers” IF num1 > num2 THEN IF num1 > num3 THEN PRINT “num1 is largest” ELSE PRINT “num3 is largest” END IF ELSE IF num2 > num3 THEN PRINT “num2 is largest” ELSE PRINT “num3 is largest” END IF END IF

Repetition in algorithm refers to performing operations (Set of steps) repeatedly for a given number of times (till the given condition is true).
Repetition is also known as Iteration or Loop

Repetitions are written in algorithm is as follows:

While <condition>, repeat step numbers Steps to be taken when condition is true End while

Algorithm, Pseudocode, Flowchart with Repetition ( Loop ) Examples

Example: write an algorithm, pseudocode and flow chart to display “Techtipnow” 10 times

Step1: Set count = 0 Step2: while count is less than 10, repeat step 3,4 Step 3: print “techtipnow” Step 4: count = count + 1 Step 5: End while

SET count = 0 WHILE count<10 PRINT “Techtipnow” Count = count + 1 END WHILE

Example: Write pseudocode and flow chart to calculate total of 10 numbers

Step 1: SET count = 0, total = 0 Step 2: WHILE count < 10, REPEAT steps 3 to 5 Step 3: INPUT a number in var Step 4: COMPUTE total = total + var Step 5: count = count + 1 Step 6: END WHILE Step 7: PRINT total

Example: Write pseudo code and flow chart to find factorial of a given number

Step 1: SET fact = 1 Step 2: INPUT a number in num Step 3: WHILE num >=1 REPEAT step 4, 5 Step 4: fact = fact * num Step 5: num = num – 1 Step 6: END WHILE Step 7: PRINT fact

Decomposition

Decomposition means breaking down a complex problem into smaller sub problems to solve them conveniently and easily.
Breaking down complex problem into sub problem also means analyzing each sub problem in detail.
Decomposition also helps in reducing time and effort as different subprograms can be assigned to different experts in solving such problems.
To get the complete solution, it is necessary to integrate the solution of all the sub problems once done.

Following image depicts the decomposition of a problem

2 thoughts on “Introduction to Problem Solving Class 11 Notes | CBSE Computer Science”

SO HELPFUL AND BEST NOTES ARE AVAILABLE TO GAIN KNOWLEDGE EASILY THANK YOU VERY VERY HEPFUL CONTENTS

THANK YOU SO MUCH FOR THE WONDERFUL NOTES

Introduction to problem solving Computer Science Class 11 Notes

This article – introduction to problem solving Computer Science Class 11 offers comprehensive notes for Chapter 4 of the CBSE Computer Science Class 11 NCERT textbook.

Topics Covered

Introduction to problem solving Computer Science class 11

Computers, mobiles, the internet, etc. becomes our essentials nowadays for our routine life. We are using the to make our tasks easy and faster.

For example, earlier we were going to banks and standing in long queues for any type of transaction like money deposits or withdrawals. Today we can do these tasks from anywhere without visiting banks through internet banking and mobiles.

Basically, this was a complex problem and solved by a computer. The system was made online with the help of computers and the internet and made our task very easy.

This process is termed “Computerisations”. The problem is solved by using software to make a task easy and comfortable. Problem solving is a key term related to computer science.

The question comes to your mind how to solve a complex problem using computers? Let’s begin the article introduction to problem-solving Computer Science 11.

Introduction to problem solving Computer Science Class 11 – Steps for problem solving

“Computer Science is a science of abstraction -creating the right model for a problem and devising the appropriate mechanizable techniques to solve it.”

Solving any complex problem starts with understanding the problem and identifying the problem.

Suppose you are going to school by your bicycle. While riding on it you hear some noise coming from it. So first you will try to find that from where the noise is coming. So if you couldn’t solve the problem, you need to get it repaired.

The bicycle mechanic identifies the problem like a source of noise, causes of noise etc. then understand them and repair it for you.

So there are multiple steps involved in problem-solving. If the problem is simple and easy, we will find the solution easily. But the complex problem needs a few methods or steps to solve.

So complex problem requires some tools, a system or software in order to provide the solution. So it is a step-by-step process. These steps are as follows:

Analysing the problem

Developing an algorithm, testing and debugging.

The first step in the introduction to problem solving Computer Science Class 11 is analyzing the problem.

When you need to find a solution for a problem, you need to understand the problem in detail. You should identify the reasons and causes of the problem as well as what to be solved.

So this step involves a detailed study of the problem and then you need to follow some principles and core functionality of the solution.

In this step input and output, elements should be produced.

The second step for introduction to problem solving Computer Science class 11 is developing an algorithm.

An algorithm is a step-by-step process of a solution to a complex problem. It is written in natural language. An algorithm consists of various steps and begins from start to end. In between input, process and output will be specified. More details we will cover in the next section.

In short, the algorithm provides all the steps required to solve a problem.

For example:

Finding the simple interest, you need to follow the given steps:

Gather required information and data such as principle amount, rate of interest and duration.
Apply the formula for computing simple interest i.e. si=prn/100
Now store the answer in si
Display the calculated simple interest

In the above example, I have started and completed a task in a finite number of steps. It is completed in 4 finite steps.

Why algorithm is needed?

The algorithm helps developers in many ways. So it is needed for them for the following reasons:

It prepares a roadmap of the program to be written before writing code.
It helps to clearly visualise the instructions to be given in the program.
When the algorithm is developed, a programmer knows the number of steps required to follow for the particular task.
Algorithm writing is the initial stage (first step) of programming.
It makes program writing easy and simple.
It also ensures the accuracy of data and program output.
It increases the reliability and efficiency of the solution.

Characteristics of a good algorithm

The characteristics of a good algorithm are as follows:

It starts and ends with a finite number of steps. Therefore the steps are precisely stated or defined.
In the algorithm, the result of each step is defined uniquely and based on the given input and process.
After completion of the task, the algorithm will end.
The algorithm accepts input and produces the output.

While writing the algorithm the following things should be clearly identified:

The input required for the task
The computation formula or processing instructions

After writing the algorithm, it is required to represent it. Once the steps are finalised, it is required to be represented logically. This logical representation of the program clearly does the following:

Clears the logic of the program
The execution of the program

The algorithm is steps written in the form of text. So it is difficult to read sometimes. So if it is represented in pictorial form it would be better for analysis of the program.

The flowchart is used to represent the algorithm in visual form.

Flowchart – Visual representation of an algorithm

A flowchart is made of some symbols or shapes like rectangles, squares, and diamonds connected by arrows. Every shape represents each step of an algorithm. The arrow basically represents the order or link of the steps.

The symbols used in the flow chart are as follows:

flow chart symbols introduction to problem solving computer science class 11

Coding is an essential part of the introduction to problem solving ComputerScience11.

It is pronounced as soo-doh-kohd
It is one of the ways of representing algorithms in a systematic way
The word pseudo means not real, therefore pseudocode means not real code
It is non-formal language, that helps programmers to write code
It is written in human understandable language
It cannot be directly read by computers
There is no specific standard or way of writing pseudocode is there

When an algorithm is prepared, the next step is writing code. This code will be written in a specific programming language. The code follows certain rules and regulations of the programing language and provides solutions.

When coding is done you need to maintain it with proper documentation as well. The best practices for coding procedures must be followed. Because this code can be reviewed a number of times for further development and upgradation.

Let’s understand this step with a simple example!!

When your mother prepares a cake at your home, she will give peace of cake to someone before serving it to check the taste of the cake, right!!! If anything is needed like sugar or softness or hardness should be improved she will decide and do the improvement.

Similarly after writing code testing and debugging are required to check the software whether is providing the solution in a good manner not.

Have look at this also: Computer Science Class XI

By Sanjay Parmar

More on this, computer science class 11 sample paper 2023-24 comprehensive guide, split up syllabus computer science class 11 comprehensive guide, comprehensive notes types of software class 11, leave a reply cancel reply.

You must be logged in to post a comment.

Class 6 Maths
Class 6 Science
Class 6 Social Science
Class 6 English
Class 7 Maths
Class 7 Science
Class 7 Social Science
Class 7 English
Class 8 Maths
Class 8 Science
Class 8 Social Science
Class 8 English
Class 9 Maths
Class 9 Science
Class 9 Social Science
Class 9 English
Class 10 Maths
Class 10 Science
Class 10 Social Science
Class 10 English
Class 11 Maths
Class 11 Computer Science (Python)
Class 11 English
Class 12 Maths
Class 12 English
Class 12 Economics
Class 12 Accountancy
Class 12 Physics
Class 12 Chemistry
Class 12 Biology
Class 12 Computer Science (Python)
Class 12 Physical Education
GST and Accounting Course
Excel Course
Tally Course
Finance and CMA Data Course
Payroll Course

Interesting

Learn English
Learn Excel
Learn Tally
Learn GST (Goods and Services Tax)
Learn Accounting and Finance
GST Tax Invoice Format
Accounts Tax Practical
Tally Ledger List
GSTR 2A - JSON to Excel

Are you in school ? Do you love Teachoo?

We would love to talk to you! Please fill this form so that we can contact you

You are learning...

Chapter 4 Class 11 - Introduction to Problem Solving

Click on any of the links below to start learning from Teachoo ...

Do you want to learn how to solve problems using computers? Do you want to develop your logical thinking and programming skills ? Do you want to explore the fascinating world of algorithms and data structures ? If you answered yes to any of these questions, then this chapter is for you! 🙌

In this chapter, you will learn about the basic concepts and techniques of problem solving using computers. You will learn how to:

Define a problem and its specifications 📝
Analyze a problem and identify its inputs, outputs and processing steps 🔎
Design an algorithm to solve a problem using various methods such as pseudocode, flowcharts and decision tables 📊
Implement an algorithm using a programming language such as Python 🐍
Test and debug your program to ensure its correctness and efficiency 🛠️
Evaluate your solution and compare it with other possible solutions 💯

By the end of this chapter, you will be able to apply your problem solving skills to various domains such as mathematics, science, engineering, games, art and more. You will also be able to appreciate the beauty and elegance of algorithms and data structures, and how they can help you solve complex and challenging problems. 😍

This chapter is designed for students who have some basic knowledge of computers and programming, but want to improve their problem solving abilities. It is also suitable for anyone who is interested in learning more about computer science and its applications. 🚀

MCQ questions (1 mark each)

True or false questions (1 mark each), fill in the blanks questions (1 mark each), very short answer type questions (1 mark each), short answer type questions (2 marks each), long answer type questions (3 marks each).

What's in it?

Hi, it looks like you're using AdBlock :(

Please login to view more pages. it's free :), solve all your doubts with teachoo black.

Introduction to Algorithms and Flowcharts

Problem Solving

Today, we use computers in every field for various purposes. But, we know that they cannot solve the problems all by themselves. Furthermore, we have to give step by step instructions to the computer for solving the problem. We can define problem-solving as a process of understanding the problem, finding solutions for the problem, and finally implementing the solution to it. We can design the solution before coding in the form of algorithms and flowcharts. Moreover, the identification of arithmetic and logical operations is very important in developing the program.

Therefore, we can say that a successful problem-solving process depends on the following factors:

understanding the problem and defining it precisely.
designing proper algorithms and flowcharts of the solution.
implementing the algorithm successfully.

When the problems are easy we can easily search out a solution. Whereas, complex problems require step by step process to solve. Hence, this means that we have to apply problem-solving techniques to solve the problem. Furthermore, this starts with finding a precise definition of the problem and ends with a successful solution. Moreover, the identification of arithmetic and logical operations plays a vital role while designing the algorithm. Here, we will study the algorithms and flowcharts.

Designing the solution

After understanding the relationship between input and output and the functionalities required we have to design an algorithm or flowchart. Furthermore, the algorithm should contain all the necessary functions to solve the problem. Moreover, it should produce a proper output for every input.

Hence, we can say that before writing the exact code for the problem it is necessary to define a solution. We can do this by starting with an initial plan and improvising it till it gives perfect results. Moreover, there can be more than one possible solution for a problem. Therefore, it is the responsibility of the programmer to choose the best solution.

While designing a problem we can represent it in algorithms and flowcharts. Hence, before writing the program code we can design the solution either in the form of an algorithm or a flowchart.

Browse more Topics Under Problem Solving Methodologies

Understanding of the Problem
Solution for the Problem
Breaking Down Solution into Simple Steps
Identification of Arithmetic and Logical Operations
Control Structure

Introduction to Algorithms

An algorithm is basically a procedure of steps that we exactly follow to solve a particular task or problem. We can say that it is a set of rules that we need to follow while developing a program code during problem-solving. Furthermore, if we write an algorithm before actually writing a code, it becomes easy to perform the coding part. Moreover, the algorithm is in simple English language hence, others can also easily understand it and develop the code.

Features of an algorithm

The features of an algorithm are as follows:

The algorithm should be very clear and unambiguous in its meaning. It should be simple so that one can understand it easily.

Well-defined inputs

A program may require to take input from the user. Therefore, the algorithm should clearly define the inputs.

Well-defined outputs

The algorithm should clearly specify the output that the program will produce.

The algorithm should have a termination point. This means that the algorithm should not be such that it runs infinite times or end up in loops.

Feasibility

The algorithm should be such that we can implement it easily. Hence, it should be simple and practical to implement.

Language independent

It should be in simple English language. Since the code implementation should result in the same output no matter which programming language we use while writing the code.

Introduction to Flowcharts

It is basically a diagrammatic representation of an algorithm. Furthermore, it uses various symbols and arrows to describe the beginning, ending, and flow of the program. Moreover, the programmers use it to depicting the flow of data and instructions while problem-solving. F lowcharting is the process of drawing a flowchart for an algorithm.

Symbols in a flowchart

The flowchart uses various symbols in the representation. These basic symbols are as follows:

It represents the start, stop, or halt in a program’s flow. The flowchart always starts and ends with this symbol. Besides, we represent it using an oval shape.

Input/Output

We represent it using a parallelogram . It indicates any input from the user or output of the program.

We represent it using a rectangle . It indicates any arithmetic operation’s processing such as addition, subtraction, multiplication, division, etc.

We represent it using the diamond symbol. It represents any type of decision in a program that results in true or false. For example. if-conditions.

We represent it using a circle . Whenever a flowchart is too large we can use connectors to avoid confusion.

These are basically arrows that represent the flow of the program.

Frequently Asked Questions (FAQs)

Q1. What are the main steps in problem-solving?

A1. A successful problem-solving process depends on the following factors:

understanding the problem.
designing proper algorithms and flowcharts.
implementing the algorithm.

Q2. What is problem-solving?

A2. We can define problem-solving as a process of understanding the problem, finding solution for the problem, and finally implementing the solution to it.

Q3. What is an algorithm?

A3. An algorithm is basically a procedure of steps that we exactly follow to solve a particular task or problem.

Q4. What is a flowchart?

A4. It is basically a diagrammatic representation of an algorithm. Furthermore, it uses various symbols and arrows to describe the beginning, ending, and flow of the program.

Q5. Name the features of an algorithm.

A5. The features of an algorithm are as follows:

Customize your course in 30 seconds

Which class are you in.

Problem Solving Methodologies

Control Structures
Identification of Arithmetic and Logical Operations Required for Solution
Understanding the Problem

Download the App

CBSE Revision Notes
CBSE Free Video Lectures
CBSE Important Questions
CBSE Objective (MCQs)
Assertation & Reasoning Questions
CBSE Syllabus
CBSE Sample paper
CBSE Extra Sampler Paper
Question Bank
Project, Assignments & Activities
ICSE Free Video Lectures
Class 6 ICSE Revision Notes
CLASS 7 ICSE REVISION NOTES
CLASS 8 ICSE REVISION NOTES
CLASS 9 ICSE REVISION NOTES
CLASS 10 ICSE REVISION NOTES
Class 6 ICSE Solutions
CLASS 7 ICSE Solutions
CLASS 8 ICSE Solutions
CLASS 9 ICSE Solutions
CLASS 10 ICSE Solutions
Class 6 ICSE Important Questions
CLASS 7 ICSE Important Question
CLASS 8 ICSE IMPORTANT QUESTIONS
CLASS 9 ICSE Important Questions
CLASS 10 ICSE Important Question
Class 6 ICSE Mcqs Question
Class 7 ICSE Mcqs Question
CLASS 8 ICSE MCQS QUESTION
CLASS 9 ICSE Mcqs Questions
CLASS 10 ICSE Mcqs Question
ICSE Syllabus
Class 6th Quick Revision Notes
Class 7th Quick Revision Notes
Class 8th Quick Revision Notes
Class 9th Quick Revision Notes
Class 10th Quick Revision Notes
Class 11th Quick revision Notes
Class 12th Quick Revision Notes
Class 6th NCERT Solution
Class 7th NCERT Solution
Class 8th – NCERT Solution
Class 9th NCERT Solution
Class 10th NCERT Solution
Class 11th NCERT Solution
Class 12th NCERT Solution
Class 6th Most Important Questions
Class 7th Important Questions
Class 8th Important Questions
Class 9th Most Important Questions
Class 10th Most Important Questions
Class 11th important questions
Class 12th important questions
Class 6th MCQs
Class 7th MCQs
Class 8th MCQs
Class 9th MCQs
Class 10th MCQs
Class 11th MCQs questions
Class 12th Important MCQs
NCERT Sample Paper
NCERT Books in Pdf
NCERT Chapter Mind Maps
OliveTree Books Study Materials
Forever With Books Study Material
Rs Aggrawal Solutions
RD Sharma Solution
HC Verma Solution
Lakhmir Singh Solution
T.R Jain & V.K ohri Solution
DK Goel Solutions
TS Grewal Solution
Our Products
Online Tuition Services
Career Advisor Booking
Skill Development Courses
Previous Year Board Exam Papers
Free Video Lectures

Chapter 4 : Introduction to Problem Solving | class 11th | revision notes computer science

Chapter 4 : Introduction to…

Introduction to Problem Solving

Steps for problem solving ( analysing the problem, developing an algorithm, coding, testing and debugging).
flow chart and
pseudo code,

Decomposition

Introduction

Computers is machine that not only use to develop the software. It is also used for solving various day-to-day problems.

Computers cannot solve a problem by themselves. It solve the problem on basic of the step-by-step instructions given by us.

Thus, the success of a computer in solving a problem depends on how correctly and precisely we –

Identifying (define) the problem
Designing & developing an algorithm and
Implementing the algorithm (solution) do develop a program using any programming language.

Thus problem solving is an essential skill that a computer science student should know.

Steps for Problem Solving-

1. Analysing the problem

2. Developing an Algorithm

It is essential to device a solution before writing a program code for a given problem. The solution is represented in natural language and is called an algorithm.

Algorithm: A set of exact steps which when followed, solve the problem or accomplish the required task.

Coding is the process of converting the algorithm into the program which can be understood by the computer to generate the desired solution.

You can use any high level programming languages for writing a program.

4. Testing and Debugging

The program created should be tested on various parameters.

The program should meet the requirements of the user.
It must respond within the expected time.
It should generate correct output for all possible inputs.
In the presence of syntactical errors, no output will be obtained.
In case the output generated is incorrect, then the program should be checked for logical errors, if any.

Software Testing methods are

unit or component testing,
integration testing,
system testing, and
acceptance testing

Debugging – The errors or defects found in the testing phases are debugged or rectified and the program is again tested. This continues till all the errors are removed from the program.

Algorithm is a set of sequence which followed to solve a problem.

Algorithm for Computing GCD of two numbers:

Step 1: Find the numbers (divisors) which can divide the given numbers.

Step 2: Then find the largest common number from these two lists.

A finite sequence of steps required to get the desired output is called an algorithm. Algorithm has a definite beginning and a definite end, and consists of a finite number of steps.

Characteristics of a good algorithm

Precision — the steps are precisely stated or defined.
Uniqueness — results of each step are uniquely defined and only depend on the input and the result of the preceding steps.
Finiteness — the algorithm always stops after a finite number of steps.
Input — the algorithm receives some input.
Output — the algorithm produces some output.

While writing an algorithm, it is required to clearly identify the following:

The input to be taken from the user.
Processing or computation to be performed to get the desired result.
The output desired by the user.

Representation of Algorithms

There are two common methods of representing an algorithm —

Flowchart — Visual Representation of Algorithms

Start/End – Also called “Terminator” symbol. It indicates where the flow starts and ends.

Input / Output – Also called data symbol, this parallelogram shape is used to input or output data.

Arrow – Connector to show order of flow between shapes.

The algorithm to find square of a number can be represented pictorially using flowchart

Table of Contents

It is intended for human reading and cannot be executed directly by the computer.
No specific standard for writing a pseudocode exists.
The word “pseudo” means “not real,” so “pseudocode” means “not real code”.

Keywords are used in pseudocode:

Question : Write an algorithm to calculate area and perimeter of a rectangle, using both pseudocode and flowchart.

Pseudocode for calculating area and perimeter of a rectangle.

INPUT length INPUT breadth COMPUTE Area = length * breadth PRINT Area COMPUTE Perim = 2 * (length + breadth) PRINT Perim The flowchart for this algorithm

Benefits of Pseudocode

A pseudocode of a program helps in representing the basic functionality of the intended program.
By writing the code first in a human readable language, the programmer safeguards against leaving out any important step.
For non-programmers, actual programs are difficult to read and understand, but pseudocode helps them to review the steps to confirm that the proposed implementation is going to achieve the desire output.