Introduction to Loops

Repetition

The repetition of an instruction or a group of instructions is a commonly encountered phenomenon in programming. It is called a loop. As an example, let’s say we want our program to perform the following tasks:

• To read a document or data file line by line repeatedly until the end of the file
• To draw an image pixel by pixel, repeatedly using color values that show it on the screen
• To iterate through a collection of variables one by one to process their values
• To compute a result by applying a formula to several values