Task 13. Read the text and do the exercises below

Text 14 B. STEPS IN COMPUTER PROGRAM DEVELOPMENT

Although the programmer is responsible for writing the computer program, the system analyst must communicate the computer program requirements to the programmer. The function of each program was defined for the programmer when functions were allocated during system design. Detailed data flow diagrams (DFD) are prepared for each program from the decomposed DFDs created during the design phase. These DFDs define the function of each program.

In program planning, the logic to be used to solve the problem is developed. Algorithms, computer program logic flowcharts, and structure charts are useful tools for program planning. Algorithms are sets of rules or instructions used to accomplish tasks. They may be stated as formulas, decision tables, or narratives.

The next step, writing, or coding, a program, is the actual writing of computer instructions. These instructions will be translated to machine code and followed by the computer; they should follow the steps of the program logic plan.

Several programming languages, particularly COBOL, PL/I, and RPG, are commonly used to solve business problems. In addition to these traditional languages, organizations using database management systems may choose to generate programs using the query language of the DBMS.

These query languages are part of a package of programming tools known as fourth-generation languages. Each language has its advantages and disadvantages. Most computer installations have a standard language used by their programmers. Programmers usually are not given a choice of language unless some special circumstances exist.

Testing and debugging a program involve:

· translating the coded program into machine language, a process called compilation;

· testing the translated program with sample data and checking the result.

If the results of testing are not correct, the program is said to have "bugs". Debugging is the process of correcting computer programs to obtain correct results.

The last step is to complete the documentation for the program. The documentation must include a statement of the purpose of the program, a description of the solution logic, a listing of the program instructions, and sample outputs from the completed programs. Information provided to the programmer by the analyst, such as descriptions of program inputs, outputs, and files, should be included. Instructions to operators explaining how the program is to be used must be written before the program documentation is completed.