Wednesday, July 20, 2011

Unstructured, Procedural, Modular Programming

1. Unstructured Programming

They are simple programs consists only one main program. “Main Program” stands for a sequence of commands or statements which modify data which is global throughout the whole program.

image

2. Procedural Programming

With procedural programming you are able to combine returning sequences of statements into one single place.Procedure call is used to invoke the procedure. After the sequence is processed, flow of control proceeds right after the position where the call was made.

image

Now a program can be viewed as a sequence of procedure calls. The main program is responsible to pass data to the individual calls, the data is processed by the procedures and, once the program has finished, the resulting data is presented. Thus, the flow of data can be illustrated as a hierarchical graph, a tree, as shown bellow.

image

Now we have a single program which is divided into small pieces called procedures.

3. Modular Programming

With modular programming procedures of a common functionality are grouped together into separate modules.

image

No comments: