Area of triangle = SQRT(S*(Sa)*(Sb)*(Sc)) where S=(a+b+c)/2, a, b, c are the three sides of the triangle. Define two macros with parameters, one is used to find area, and the other macro is used to find S. Write a program and use the macro name with actual parameters to find the area.
Input format
The three sides of triangle abc can be decimals.
Output format
Area of a triangle to 3 decimal places
Sample input
copy
3 4 5
Sample output
copy
6.000
#include<iostream>
#include<iomanip>
#include<cmath>
using namespace std;
#define GetS(a,b,c) ((a+b+c)/2.0)
#define GetArea(a,b,c){\
float S=GetS(a,b,c);\
float area=sqrt(S*(S-a)*(S-b)*(S-c));\
cout << fixed << setprecision(3) << area;\
}
/*这个"\"放在宏定义函数句子的末尾，表示本句结束，以及其他*/
int main() {
float a, b, c;
cin >> a >> b >> c;
GetArea(a,b,c);
return 0;
}