PROGRAM DEVELOPMENT STEPS

PROGRAM DEVELOPMENT STEPS

                        Program is combination of instructions and data. The steps involved in a program development are:-

1. Problem Specification

          This step involves analyzing the inputs provided, questions asked and output                                               specifications of the problem are specified.

2. Outlining the Solution

When once the problem is clear, there may be several methods to have a solution. The choice               is made based on time-consumed and how far it is error-free.

3. Algorithm

The solution method is described step-by-step here. The step-by-step procedure of the                           solution is an algorithm. So, an algorithm for the solution method is developed.

4. Flowchart

The algorithm prepared above has to be converted into pictorial representation for better                       understandability of the solution.

5. Coding

Coding is the process of creating, writing, editing, linking, compiling, debugging, executing                and maintaining computer code. Coding is the Executable art of program.

Executing a program involves following steps.

1. Creating the program

2. Compiling the program

3. Linking the program with library functions

4. Executing the program

Creating the program

            Once we load Operating System into the memory, the computer is ready to receive the program. The program must be entered into the file and file name must be valid and all files should be saved with “.c” extension. 

Compiling the program

            Source program instructions are now translated into a form that is suitable for execution by the computer. Compiler will examine each instruction for it’s correctness and if there are no errors, Object code or Machine code will be created.

Linking the program with library functions

            Linking is the process of putting together other program files and functions that are required by the program.

Executing the program

            The Executable object code will be loaded into memory and executes the instructions. During execution, The program may request some data from keyboard. In case of source program is modified, the entire process of compiling, linking and executing should be repeated till we get correct result.

1. Testing

 Testing is the process of finding the errors or bugs and assurance of software quality.

Errors are of mainly two types.

Ø  Syntax errors or Compile-time errors

Errors in syntax (grammar) of the program. Error message is displayed by the compiler while executing the program. Syntax errors are code errors.

Ex:- missing semicolon

Ø  Semantic or Logical Errors or Run-time errors

Errors in the meaning and Logic of the program. We get wrong outputs. Compiler cannot identify these kind of errors. 

            Ex:- divide by zero

To remove such errors we require Testing and testing can be performed in two ways..

Ø  Black Box Testing

            The functionalities involved in the program are tested here.

Eg:- calculations, input testing, error handling etc.

Ø  White Box Testing

This testing mainly concentrates on the control structure of  the program.

         Eg:- path testing, condition testing etc.

7. Debugging

            Process of deleting and removing errors is called debugging. Debugging is a methodical process of finding and reducing the number of bugs, or defects, in a computer program.

8. Documentation

     Documentation is the information that explains the usage as well as functionality of the                       software and meant for future reference.

Ø  Operational Documentation

It provides the information regarding the input and output formats, operating instructions, different kinds of user interaction with the program and limitations if any.

Ø  Technical Documentation

It provides the technical details including the design aspects and brief explanation of the procedures involved, hardware to be operated.

9. Maintenance

            Software maintenance is the modification of a software product after delivery to correct                       faults, to improve performance or to adapt the product to a modified environment.

Ø  Perfective maintenance is any modification of a software product after delivery to improve performance or maintainability.

Ø  Corrective maintenance is the reactive modification of a software product performed after delivery to correct discovered faults.

Ø  Adaptive maintenance is the modification of a software product performed after delivery to keep a computer program usable in a changed or changing environment.

Ø  Preventive maintenance refers to software modifications performed for the purpose of preventing problems before they occur.