where is the error in this program? it outputs constant values of vcone and scone for different values of r and h.

Question

//calculate volume and surface area of a cone using c++ function programe
#include<iostream>
#include<math.h>
using namespace std;
double vcone(float r,float h);
double scone(float r,float h);
int main(){
float r,h;
cout<<"enter the values of r,and h:"<<endl;
cin>>r>>h;
cout<<"volume of a cone is:"<<vcone<<endl;
cout<<"surface area of a cone is:"<<scone<<endl;
return 0;
}
double vcone(float r,float h){
    const float pi=3.142;
    float volume;
    volume=1/3.0*pi*pow(r,2)*h;
    return volume;
}
double scone(float r,float h){
    const float pi=3.142;
    float surfacacearea;
    surfacacearea=pi*r*(r+sqrt(pow(h,2)+pow(r,2)));
    return surfacacearea;
}

Answer 1

In main function, the lines should be:

cout<<"Volume of the cone is: "<<volume<<endl;

cout<<"Surface area of the cone is: "<<surfacearea<<endl;

Comments

Isn't volume and surfacearea local variables to their respective funcs. answer will be to pass r, h to vcone and scone.

cout<<"volume of a cone is:"<<vcone(r,h)<<endl;
cout<<"surface area of a cone is:"<<scone(r,h)<<endl;

Answer 2

You need to pass the parameters r and h to the functions vcone and scone, respectively, i.e. replace 

cout<<"volume of a cone is:"<<vcone<<endl;
cout<<"surface area of a cone is:"<<scone<<endl;

with 

cout<<"volume of a cone is:"<<vcone(r,h)<<endl;
cout<<"surface area of a cone is:"<<scone(r,h)<<endl;

The functions need input arguments to work. As it is you are printing the values of the function pointers.

Hope that helps.

GG