Do repetitive processing by while loop in C lang
Do repetitive processing by while loop.
while_loop.c 
#include <stdio.h>

int main(void) {
  int i = 0;
  while(i < 5) {
    printf("loop count = %d\n", i);
    ++i;
  }
  return 0;
}
Result 
$ gcc while_loop.c -o while_loop
$ ./while_loop
loop count = 0
loop count = 1
loop count = 2
loop count = 3
loop count = 4