编写重载函数area（）和perime（），分别计算圆，长方形，正方形的面积和周长，并在主函数中测试

Question

参考代码：
#include “iosteam”
#include<cmath>
using namespace std;
#define pi 3.141592
double Area(double R);
double Area(double a,double b);
double Perim(double R);
double perim(double a,duble b);
int main()
{    
double r;        
double m;   
 double n;    
cout<<"请输入圆的半径："<<endl;    
cin>>r;    
cout<<"圆的面积为："<<Area(r)<<"  "<<"圆的周长为："<<Perim(r)<<endl;    
cout<<"请输入长方形的边长："<<endl;    
cin>>m>>n;    
cout<<"长方形的面积为："<<Area(m,n)<<"  "<<"长方形的周长为："<<Perim(m,n)<<endl;    
cout<<"请输入正方形的边长："<<endl;    
cin>>m;    
cout<<"正方形的面积为："<<Area(m,m)<<"  "<<"正方形的周长为："<<Perim(m,m)<<endl;
}
double Area(double R)
{……}
double Area(double a,double b)
{……}
double Perim(double R)
{……}
double perim(double a,duble b)
{……}

Answer 1

#include <iostream>

using namespace std;

const double PI = 3.141592;

double area(double r) { return PI * r * r; }
double area(double a, double b) { return a * b; }
double perimeter(double r) { return 2.0 * PI * r; }
double perimeter(double a, double b) { return 2.0 * (a + b); }

int main() {
  double r, m, n;
  cout << "请输入圆的半径：";
  cin >> r;
  cout << "圆的面积为：" << area(r) << "  "
       << "圆的周长为：" << perimeter(r) << endl;
  cout << "请输入长方形的边长：";
  cin >> m >> n;
  cout << "长方形的面积为：" << area(m, n) << "  "
       << "长方形的周长为：" << perimeter(m, n) << endl;
  cout << "请输入正方形的边长：";
  cin >> m;
  cout << "正方形的面积为：" << area(m, m) << "  "
       << "正方形的周长为：" << perimeter(m, m) << endl;
  return 0;
}