C语言交换两个数的值

#include<stdio.h>
int main()
{
   //交换两个数的值
  // 方法一 可读性最好
    int a = ;
    int b = ;
    int temp ;
    temp = a;
    a = b;
    b = temp;
    printf("a = %d, b = %d\n",a, b);

  //方法二
    int c = ;
    int d = ;
    c = d - c;
    d = d - c;
    c = d + c;
    printf("c = %d, d = %d\n",c, d);
 // 方法三
    int e = ;
    int f = ;
    e = e ^ f;
    f = e ^ f;
    e = e ^ f;
    printf("e = %d, f = %d\n",e, f);
   return ;
}

a = , b =
c = , d =
e = , f =