3.1

(1)

# include <stdio.h>

int main()

{int s=0;

int a;

for(a=22;a<=1002;a+=20)

{s=s+a; }

printf("%ld\n",s);

return 0;

}

(2)

#include "stdafx.h"

int main(int argc, char* argv[]) {  int s=0;  int a=22;  while (a<=1002)  {s=s+a; a=a+20; }  printf("%ld\n",s);  return 0; }

(3)

#include "stdafx.h"

int main(int argc, char* argv[]) {  int s=0;  int a=22;  do{s=s+a;  a=a+20;  }  while(a<=1002);  printf("%d\n",s);

 return 0; }