【C++】primer plus 练习7.1

//计算调和平均数#include<iostream>float count(float n,float m);int main(){using namespace std;float a,b,num;cout<<"Please enter two number:\n";while(cin >>a>>b){if(a ==0||b==0)                   //输出0结束break;num =count(a,b);cout<<"Harmonic mean: "<<num<<endl; // 调和平均数cout<<"Again enter two number:\n";}cout <<"End!\n";return 0;}float count(float n,float m){return 2.0*n*m/(n+m);}