c语言"##"的使用

#include<stdio.h>
#define Operations(x) operation_ ## x  // ## 是黏贴字符串

int Operations(sum)(int x,int y){  // operation_sum(int x,int y)
    return x+y;
}

int Operations(sub)(int x,int y){  // operation_sub(int x,int y)
    return x-y;
}

int Operations(mul)(int x,int y){  // operation_mul(int x,int y)
    return x*y;
}

float Operations(div)(float x,float y){  // operation_div(int x,int y)
    float result;
    result =x/y;
    return result;
}

#define Print(x) printf("%s,%d\n",#x,x);  // # 表示将参数转变为字符串
int main()
{
    int x;
    float y;
    x=Operations(sum)(,);
    printf("x=%d\n",x);
    x=operation_sum(,);
    printf("x=%d\n",x);
    x=Operations(sub)(,);  // operation_sub(10,20)也可以
    printf("x=%d\n",x);
    x=Operations(mul)(,);  // operation_mul(10,20)也可以
    printf("x=%d\n",x);
    y=Operations(div)(,);  // operation_div(11,20)也可以
    printf("y=%lf\n",y);
    Print();
    return ;
}

注：##连接两边字符串。