After the problem has been defined, the next step is to select the best method for solving it. This commonly involves determining the sequence of processing steps within individual programs. To save on time and effort, the programmer refers to a pictorial representation, the program flowchart. The flowchart is an all-purpose tool and a program blueprint. The programmer constructs the flow chart to lay out the program logic – that is, to plan the processing steps in the program. After the programmer has tentatively established that main line of the program logic, large segments are extracted to be described in more detail on supplementary program flowcharts. This technique is called modular program flowcharting.
Coding the Solution .
Once the programmer is satisfied that all processing steps have been identified and all alternatives and exceptions provided for, the program is then made. The program flowchart serves as a guide in coding. In the coding phase, the programmer converts the steps depicted in the program flow chart into readable instructions that make up the actual program. Coding can be written at different at different levels, ranging from machine language to high-level programming languages.
Checking Out the Program .
Experience will prove that a program seldom executes successfully the first time. Even the simplest programs contain errors, and even experienced programmers make mistakes. It has been said that a program that runs correctly the first time is a rare as a hole-in-one golf. As computer programs become increasingly complex, more and more of the programmer's time is spent in program checkout – debugging and testing each new or modified program. Debugging is the task of finding program errors (bugs) and correcting them so that the program runs correctly. Testing consists of running the program with the input data that stimulates, or is a representative sample of, the actual data that will be processed by the program.
