C语言宏中#、##运算符的使用
#include <stdio.h>
#define P1(a) printf("%s^2 = %d\r\n", #a, (a)*(a))
#define P2(x) printf(#x"^2 = %d\r\n", (x)*(x))
#define F1(i,a) fun##i(a)
#define F2(fun,i,a) fun##i(a)
int x = 6;
int y = 7;
void fun1(int a) {printf("fun1(%d)\r\n", a);}
void fun2(int a) {printf("fun2(%d)\r\n", a);}
void tsk1(int a) {printf("tsk1(%d)\r\n", a);}
void tsk2(int a) {printf("tsk2(%d)\r\n", a);}
int main(int argc, char *argv[])
{
printf("Hello C-Free!\n");
P1(3);//printf("%s^2 = %d\r\n", "3", (5)*(5));
P1(x);//printf("%s^2 = %d\r\n", "x", (x)*(x));
P2(5);//printf("5""^2 = %d\r\n", (5)*(5));
P2(y);//printf("y""^2 = %d\r\n", (y)*(y));
F1(1,5);//fun1(5);
F1(2,y);//fun2(y);
F2(fun,1,5);//fun1(5);
F2(tsk,2,x);//tsk2(x);
getchar();
return 0;
}