C macro陷阱

C macro陷阱.c

#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[]) {
	#define PI 3.14159
	#define Square(x) x*x
	#define Square_(x) x*(x)
	#define Square__(x) ((x)*(x))
	
	printf("%f\n", PI);
	printf("\n");
	
	printf("%d\n", Square(5));
	printf("%d\n", Square(2+3));
	printf("\n");
	
	printf("%d\n", Square_(5));
	printf("%d\n", Square_(2+3));
	printf("\n");
	
	printf("%d\n", Square__(5));
	printf("%d\n", Square__(2+3));
	printf("\n");
	
	int i;
	i = 4;
	printf("%d\n", Square__(i++));
	
	return 0;
}