C Loops

Loops

Loops are used to repeat a block of code. A loop lets you write a very simple statement to produce a significantly greater result simply by repetition.

Example 1

#include <stdio.h>
#include <stdlib.h>
 
int main()
{
    int forX = 0;
    int whileX = 0;
    int doX = 0;
 
    /* The loop goes while x < 10, and x increases by one every loop*/
    for ( forX = 0; forX < 10; forX++ ) 
    {
        /* Keep in mind that the loop condition checks 
           the conditional statement before it loops again.
           consequently, when x equals 10 the loop breaks.
           forX is updated before the condition is checked. */   
        printf( "%d\n", forX );
    }
 
  while ( whileX < 10 ) 
   { /* While whileX is less than 10 */
      printf( "%d\n", whileX );
      whileX++;             /* Update whileX so the condition can be met eventually */
   }
 
   do 
   {
       /* "Hello, world!" is printed at least one time
       even though the condition is false*/
       printf( "%d\n", doX );
  } while ( doX != 0 );
 
  getchar();
}

Break, Continue

The break command will exit the most immediately surrounding loop regardless of what the conditions of the loop are. Break is useful if we want to exit a loop under special circumstances.

Example 2

#include <stdio.h>
#include <stdlib.h>
 
int main()
{
    int forX = 0;
    int whileX = 0;
    int doX = 0;
 
    /* The loop goes while x < 10, and x increases by one every loop*/
    for ( forX = 0; forX < 10; forX++ ) 
    {
        if(forX == 5)
            break;
        printf( "%d\n", forX );
    } 
  getchar();
}