Writing a computer program, no matter which kind, entails a few basic principles.
Declare
Input
Process
Output
Declarations
Define messages and values. All the text in dialogs and messages must be defined. Any constants, such as formulas, must be defined, as well as starting and ending points, which are often part of the programming statement, such as
if x > 100 and x < 1000.
Input/Output
All input and output must be defined. A "handle" to a file or some stream of input or output is generated, so that the programmer can say "input from this device" and "output to that device."
Process - Calculate, Compare and Copy
The heart of programming is creating the logic to process the data by calculating, comparing and copying (see the 3'Cs in
computer). The logic that one programmer conceives may be considered ridiculous by another programmer, and the logic can be as convoluted as the labyrinth minds of human beings. However, the fact is that almost any reasonably intelligent, left-brained person can learn to write a computer program. All programs employ the same, basic logic, as follows: