C++ While Loop

                                       C++ While Loop

Loops are used in programming to repeat a specific block of code. 

There are 3 type of Loops  in C++ Programming :

• for Loop

• while Loop

• do....while Loop

C++ while Loop

The syntex of a while loop is :

Where, testExpression is checked on each enty of the while loop.

How while loop works ? 

• The while loop evaluates the test expression.

•  If the test expression is true, codes inside the body of while loop is evaluated.

• Then, the test expression is evaluated again. this process goes on the test expression is false.

• When the test expression is false, while loop is terminated.

Flowchart of while Loop

Example  : C++ while Loop :

Output :

In this program , user is asked to enter a  positive integer which is stored in variable number.

Let's suppose, User entered 4.

Then , the while loop states executing the code. Here's ow while loop works:

1. Initially, i = 1 , test expression i <= number is true and factorial becomes 1.

2. Variable i is updated to 2, test expression is true, factorial becomes 2.

3. Variable i is updated to 3, test expression is true, factorial becomes 6.

4. Variable i is updated to 4, test expression is true, factorial becomes 24.

5. Variable i is updated to 5, test expression is false and while loop is terminated.