Problem Solving

Introduction to problem solving: Steps for problem solving (analysing the problem, developing an algorithm, coding, testing and debugging). representation of algorithms using flow chart and pseudo code, decomposition

Problem Analysis in Computer programming is a way where problems are discussed for giving the solution. We define data ,input and output of our program

Algorithm

An Algorithm is a step by step procedure to solve a given problem.

For example, the algorithm to find the remainder of given two numbers is:

1. Input first the number.

2. Input second number.

3. Divide first number with second number and store the remainder as

third number.

4. Display the result.

It is a set of ordered and finite steps to solve a given problem.

An algorithm should always have a clear stopping point.

Qualities of a good algorithm

1.Inputs and outputs should be well defined .

2.Each steps in algorithm should be clear.

3.Algorithm should be most effective to solve a problem.

4.An algorithm shouldn't have computer code. Instead, the algorithm should be written in such a way that, it can be used in all programming languages.

Write an algorithm to find the factorial of a number entered by user.

Step 1: Start

Step 2: Declare variables n,factorial and i.

Step 3: Initialize variables     

   factorial=1   

  i=1

Step 4: Read value of n

Step 5: Repeat the steps until i=n

  factorial=factorial*i

  i=i+1

Step 6: Display factorial

Step 7: Stop

Problem Solving  using Decomposition

The process of breaking down a complex problem into smaller parts that are more manageable and easier to understand a problem or situation better is known as decomposition .

The smaller parts can then be examined and solved, or designed individually, as they are simpler to work with.

Pseudocode :

Is informal way of describing the steps of a program's solution without using any strict  programming language syntax.

In Pseudocode , usually  the instructions are written in upper case , variables in lowercase and messages are in sentence case.

Advantages of pseudocode –

• Pseudocode is understood by the programmers of all types.

• it enables the programmer to concentrate only on the algorithm part of the code development.

• It cannot be compiled into an executable program. 

Disadvantages :

It is not a visual tool like flowchart

It is an informal representation of an algorithm

Example, 

Java code : if (i < 10) { i++; } 

pseudocode :

if i is less than 10, increment i by 1.

Another example

Example:

if "1"

    print response

        "I am case 1"

if "2"

    print response

        "I am case 2"