#include <stdio.h>
void main ()
{
    int a=0,b=0,c=0,d=20,x;
    if (a) d=d-10;
    else if (!b)
        if (!c)
            x=15;
        else
            x=25;
        printf ("d=%d ,x=%d\n",d,x);
   
}

谢谢了，懂了