#include <iostream>
#include <cmath>
using namespace std;
double AM(double a, double b) {
return (a+b)/2;
}// AM = (a + b + c + d + e)/5
double GM(double a, double b) {
if(a*b < 0){
return -1;
}else{
return pow(a*b,0.5);
}
}// GM = (abcde)^(1/5)
double HM(double a, double b) {
if(a == 0 || b == 0){
return -1;
}else{
return 1/((1/a + 1/b)/2);
}
}// GM = 1/ ((1/a + 1/b +1/c + 1/d + 1/e)/5)
double mean(double a, double b, int meanType = 0){
if(meanType == 0) return AM(a,b);
if(meanType == 1) return GM(a,b);
if(meanType == 2) return HM(a,b);
}
int main() {
cout << "The arithmetic mean of 3 and 5 is: " << mean(3, 5) << endl;
cout << "The geometric mean of 3 and 5 is: " << mean(3, 5, 1) << endl;
cout << "The harmonic mean of 3 and 5 is: " << mean(3, 5, 2) << endl;
return 0;
}
