连等初始化问题

#include<stdio.h>
int main()
{
//int a = b = 20; //b未声明 所以不可以连等在定义的时候
int c, d;
c = d = 3;
int f;
int e = f = 4;
int m;
int n = (m = 20);
printf("%d ,%d ,%d ,%d ,%d ,%d\n",c,d,e,f,m,n);

}
//output
3, 3, 4, 4, 20, 20
请按任意键继续. . .