While Loops

While loops are very similar to and somewhat simpler than for loops. They contain a condition and the code in the loop is executed as long as the condition is true. The general form is shown below. 
    while (  )
    {
        /*code that is repeated*/
    }

The condition has the same form as the condition in an if clause and can also include boolean operators. The sequence of operations is as follows: 

1.  check the condition and if it is false, terminate the loop (go to step 4)
2.  execute the code within the braces
3.  go to step 1 and repeat
4.  continue execution of the program past the last brace in the while loop
An example while loop is shown below. It performs the same task as the for loop, adding the numbers from 1 to 100: 

#include <stdio.h>

int main(int argc, char* argv[])
{
    int i, sum = 0;

    //must do the initialization before the loop    
    i = 1;
	
    while ( i <= 100 ) 	/*checks the condition and executes the loop while
				the condition is true.*/
    {
        sum = sum + i;
        i ++; //must include the update within the loop code
    }

    printf("The sum of the numbers from 1 to 100 is: %d\n", sum);

    return 0;
}

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