#define name string 定義字串
#define name expression 巨集指令
// Example 824: macro instruction
#include <stdio.h>
#include <stdlib.h>
#define flower 8
#define say "happy birthday"
#define area r*r*3.14
int main()
{
printf("%d\n", flower * 1314);
// there is no "" for string defined
printf(say"\n");
int r;
printf("enter the radius: ");
scanf("%d", &r);
// using %f because of 3.14 (float)
printf("area = %f\n", area);
system("pause");
return 0;
}