Why Program a Computer

If there are arithmetic or computational tasks that need to be performed over and over such as evaluate a stock portfolio, calculate a payroll or balance family finances, it is faster, easier and more accurate to have a computer perform the task. All programs should be written using a text editor and saved in a file on your computer. Then they can be re-executed with new or updated data whenever needed. If a program is saved in a file, it can be easily copied and modified to make a new program. If a new program had to be written for every new problem, we would be swamped with programming tasks.

A computation occurs when a sequence of commands (the program) is executed by a computer on a specific set of data. Frequently the data is stored in the form of a table. By comparing different problems or their tables and programs, it is sometimes clear that the only difference between them is the values of the data. Thus the program for the first problem can be used for the second. The ability to use the same program over and over with different data is a very important aspect of computing.