要点：等价替换，注意运算符号优先级问题导致的错误。
示例代码：
//宏定义交换两个值 #include <stdio.h> #define SWAP(type,a,b) {type temp;temp=a;a=b;b=temp;} int main() { short int i1,i2; double d1,d2; long l1,l2; scanf("%hd%hd",&i1,&i2); SWAP(short int,i1,i2); printf("%hd %hd\n",i1,i2); scanf("%lf%lf",&d1,&d2); SWAP(double,d1,d2); printf("%g %g\n",d1,d2); scanf("%ld%ld",&l1,&l2); SWAP(long,l1,l2); printf("%ld %ld\n",l1,l2); return 0; } //弧度制转换 #include <stdio.h> #define PI 3.14159 #define AngleToRadian(degree,minute,second) (degree)/360*2*PI + minute/360/60*2*PI + second/360/60/60*2*PI int main() { double degree,minute,second; scanf("%lf %lf %lf",°ree,&minute,&second); printf("%f",AngleToRadian(degree,minute,second)); /*参数宏会被替换为定义的表达式，算出结果后输出*/ return 0; }