c语言中函数式宏

001、

#include <stdio.h>

#define diff(x, y) (x - y)        ## 函数式宏， diff函数中的参数，将按照 （x -y）在函数中展开

int main(void)
{
    int a, b; double m, n;
    
    printf("a = "); scanf("%d", &a);
    printf("b = "); scanf("%d", &b);
    printf("m = "); scanf("%lf", &m);
    printf("n = "); scanf("%lf", &n);
    
    printf("int: %d\n", diff(a, b));
    printf("double: %f\n", diff(m, n));
    
    return 0;
}