C++开学第一次作业(5.4)

开学第一次作业(5.4)

#include <iostream>
#include"area.h"
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

int main(int argc, char** argv)
{
double r;
cin >> r;
cout << area(r) << endl;
return 0;
}

#include"area.h"
double area(double r)
{
cout << r*r*PI ;
}

#include<cmath>
#include<iostream>
#define PI acos(-1)
using namespace std;
double area(double r);