求C++答案：编写两个函数,一个求圆的面积,另一个求圆的周长,然后在主函数中调

#define PI 3。14#includeusing namespace std;double area(float i){return (PI*i*i);}double circumference(float i){return 2*PI*i;}int main(){float r;double Area,Circumference;cin>>r;Area=area(r);Circumference=circumference(r);cout