宏定义的细节问题

示例代码：

#define PERIMTER(X,Y) 2*X+2*Y
int main()
{
	int length = 5;
	int width = 2;
	int high = 8;
	int result = 0;
	result = PERIMTER(length,width)*high;
	printf("result = %d \n" , result);
}

问题分析：

上述代码是实现计算长方体体积，先通过宏计算出矩形周长，再乘以高。但实际结果为42，计算错误，原因是，宏定义只是文本替换，替换后的语句为：

result = 2*length + 2*width*high;

正确代码：

#define PERIMTER(X,Y) (2*X+2*Y)
int main()
{
	int length = 5;
	int width = 2;
	int high = 8;
	int result = 0;
	result = PERIMTER(length,width)*high;
	printf("result = %d \n" , result);
}

宏定义的细节问题

原文：http://blog.csdn.net/u011421608/article/details/44316955