indefinite loop: empty for : For statement « Statement « C Tutorial

1. C Tutorial
2. Statement
3. For statement

#include <stdio.h>
#include <ctype.h>           /* For tolower() function */

int main(void)
{
  char answer = 'N';

  printf("\nThis program calculates the average of any number of values.");

  for( ;; )                           /* Indefinite loop */
  {
    printf("Do you want to enter another value? (Y or N): ");
    scanf(" %c", &answer );

    if( tolower(answer) == 'n' ){
      break;
    }
  }

  return 0;
}

This program calculates the average of any number of values.Do you want to enter another value? (Y o
     r N): N