c语言中使用函数式宏返回不同数据类型的值的平方

#include <stdio.h>

#define sqr(x) ((x) * (x))

int main(void)
{
    int a;
    puts("please input an integer.");
    printf("a = "); scanf("%d", &a);
    printf("sqr of a   : %d\n\n\n", sqr(a));
    
    double b;
    puts("please input an real number.");
    printf("b = "); scanf("%lf", &b);
    printf("sqr of b   : %f\n", sqr(b));
    
    return 0;
}