根据给出的主函数，编写两次调用的area()函数

#include<iostream>

using namespace std;

#define PI 3.1415926

float area(float r)
{
return PI*r*r;
}

float area(float a,float b)
{
return a*b;
}

void main()

{

float a,b,r;

cout<<"输入圆半径：";

cin>>r;

cout<<"圆面积："<<area(r)<<endl;

cout<<"输入矩形长宽：";

cin>>a>>b;

cout<<"矩形面积："<<area(a,b)<<endl;

}