The While Statement

• A loop is a control structure that causes a statement to be executed repeatidly.
• But not forever (that would be an infinate loop)
• The while statement

  • 
    while (expression) 
       statementA
    statementB
       

  • Evaluate the expression, while it is true execute statementA, then execute statementB
  • There must be something in the body of the loop that brings us closer to exiting from the loop.
  • A code block is applicable here for loops with multiple instructions in their bodies.

  • 
    while (expression) {
        body
    }
    	  

  • Rules for indentation apply
  • Some Definitions
    • Loop Entry - The first statement in the body of the loop
    • Iteration - one pass through the loop
    • Loop Test - The point at which the expression is evaluated
    • Loop exit - the point control passes to when the loop test fails
    • Termination condition - the condition that causes exit from th e loop.
  • Write a program that counts from 1 to 25
  • Write a program that counts from 1 to 25 by 2
  • Write a program that counts from 25 to 1.
  • Write a program that will ask a question until the desired answer is given.
  • A counter controlled loops is a loop that executes a given number of times
  • A event controlled loop is a loop that executes until an event occurs.
  • Assume a number of values is stored in a file, find the maximum, minimum and average value.