Programming Concepts

 Programming Basics   

A computer program is a set of code written in a computer language. It is executed on a computer to perform particular tasks on the computer. Programmers developed the code using a programming language. In other words, Programming is the process of creating a set of instructions to perform a task on the computer. Programming is the process of giving machines a set of instructions that describe how a program should be carried out.

Programming can be done using a variety of computer programming languages, such as JavaScript, Python, C, Java and C ++.

 Examples of compiled programming languages would be C and C++.

Program Development

Algorithm:

It is a set of instructions for solving a problem step by step. It is a list of steps to complete a task or

 solve a given problem. Example – Algorithm to find the area of the Rectangle.

1. Start
2. Take length and breadth as input
3. Calculate area of rectangle –> area = length x breadth
4. Display area of the rectangle
5. Stop

Program:

It is the implementation of Algorithm in a computer language. It is executed by the computer to accept length and breadth of the rectangle, computer then calculate the area and display the area on the screen.

#include<iostream.h>
int main()
{
 int length, breadth, area;
 cout<<"\n Enter Length";
 cin>>length;
 cout<<"\n Enter Breadth";
 cin>>breadth;
 area = length * breadth;
 cout<<"\n Area<
 return 0;
 }

When above code is executed on computer.

Program Logic:

It is the order or the sequence in which the steps are to be followed or the instructions to be executed to solve the given problem or accomplished a task. For example, in the above code, area cannot be calculated without accepting the length and breadth of the rectangle.

Representation of Program Logic:

A customer when requires to construct house or an apartment, approaches architect. Architect acquires the complete requirements from the customer. Then the architect creates the model or the blue print. The customer verifies it as per the requirements; if not model will be redesigned until the customer requirements are met.

Programmers use the same approach in designing and developing the programs. Once the developer understands the complete requirements, prepares the flowchart to represent the program logic or defines the steps in English like language.

Pseudo Code:

It describes the algorithm in a English like language that can be easily used to develop the code.  It is used for creating an outline or a rough draft of a program. Pseudo code summarizes a program's flow, but does not include underlying details of the Algorithm.

Following is the Pseudo code to accept length and breadth of Rectangle and display its area.

1     Start

2   Accept Length and breadth

3.    Calculate area

4.    Display area

5.     stop

Flowchart:

It is the pictorial or graphical representation of the program logic. A picture worth a thousand words. A flowchart is also defined as a diagrammatic representation of an algorithm, a step-by-step approach to solve a task or solve a problem.

The flowchart to accept length and breadth of rectangle and display its area is shown below:

A computer program is based on an algorithm (a sequence of activities). An algorithm is represented using pseudo code (steps in English text statements) or a flowchart (pictorial or a graphical representation to indicate the flow of action).

Pseudo code and flowcharts are used to help programmers to understand the algorithm correctly to plan and develop their proposed program.

Variable

A variable in programming world is a name given to a memory location. A computer takes data to be processed as input and stores in main memory i.e. RAM. The program instructions access data from memory process it and store results of computation in main memory. The question is how the program knows the location of data in memory. The memory location is a given a name called a variable in programmers world.

Language used in Flowchart and Pseudo class:

1. Display or Print or Output

Print “hi friends!!!”	Used to display a message on the screen or output device.
Print area	Used to display the contents of the variable area
Print “Area = “, area	Used to display both message and contents of the variable area.

1)      Accept or Read or Input

It used to accept or take input from the user through the Input Device and store in main memory.

Example; Input length, It takes a value from the keyboard and stores in the main memory location named length.

 Processing Statement

It is used to indicate processing i.e. performing arithmetic operations.

Example: - area = length * breadth, means get the contents of the memory location named length and breadth, multiply and store the result in memory location named area.

Flowchart Symbol