sqrt problem

I'm trying to get a math program I'm writing to work but I can't get the sqrt function thing to work, can someone tell me what the problem is?

Code:

  case 3:
       float cone(float r, float h, float s);
       cout<<"What is the radius of the base?"; cin>> r ; cout<<">>>\n\n";
    
       cout<<"What is the height of the cone?"; cin>> h ; cout<<">>>\n\n";
    
       s = sqrt * (r * r + h * h);   <--- This is the error line
    
       cout<<"The area of the base is: "<< 3.14159265358979323846 * (r * r) <<"\n\n";
    
       cout<<"The surface area of the triangle is: "<< 3.14159265358979323846 * r * (r+s) <<"(requires the slope)\n\n";
    
       cout<<"The height of the sloped side is: "<< s <<"(only valid if radius and height are given)\n\n";
    
       cout<<"The volume of the cone is: "<< 3.14159265358979323846 * r * r * h/3 <<"\n\n"; 
       break;

Also when I go to compile I get this error message at the bottom...

"invalid operands of types `double ()(double)' and `float' to binary `operator*' "

I'm using float number since I need pi.

Try

Code:

    s = sqrt(r * r + h * h);

Oh! I see now, I'm multiplying the square root.. thanks for pointing that out

>> float cone(float r, float h, float s);

I don't know what you intend by this line, but what it actually is is a declaration of a function named 'cone' that takes 3 floats for arguments and returns a float. To be normal you could say

Code:

float r, h, s;

In place of that. But who wants to be normal? To be funky, you could be like

Code:

struct cone 
{ 
    float r, h, s; 

    float surfaceArea() { /* implementation */ }
    float baseArea() { /* implementation */ }
    float slopeHeight() { /* implementation */ }
    float volume() { /* implementation */ }
} c;

cin >> c.r >> c.h >> c.s; cout << blather_bloother_toother;

Note: If you #define _USE_MATH_DEFINES before #including <cmath> than you can use the M_PI symbol.

Yyyyyyyeah..... I'm like brand new at C++, I started yesterday, so far this is my most advanced program:

Code:

#include <iostream>
#include <math.h>

using namespace std;

float r, h, s;
int n;
	
int main()
{
  int input;
  
  cout<<"\n\n              ============ Welcome to the Round shapes program ============\n\n\n";
  while (input != 4){
  cout<<"             1. Circle\n";
  cout<<"             2. Sphere\n";
  cout<<"             3. Cone\n";
  cout<<"             4. Exit\n\n\n";
  cout<<"Selection: ";
  cin>> input;
  switch ( input ) {
  case 1:
       float circle(float r);
       cout<<"What is the radius of the circle?"; cin>> r ; cout<<">>>\n\n";
       
       cout<<"The circumference of the circle is: "<< (2 * r) * 3.14159265358979323846 <<"\n\n";
       
       cout<<"The area of the circle is: "<< 3.14159265358979323846 * (r * r) <<"\n\n";
       break;
       
  case 2:
       float circle(float r);
       cout<<"What is the radius of the circle?"; cin>> r ; cout<<">>>\n\n";
       
       cout<<"The surface area of the sphere is: "<< 4 * 3.14159265358979323846 * (r*r*r) <<"\n\n";
       
       cout<<"The volume of the sphere is: "<< (4 * 3.14159265358979323846)/3 * (r*r*r) <<"\n\n";
       break;
       
  case 3:
       float cone(float r, float h, float s);
       cout<<"What is the radius of the base? >>>"; cin>> r ; cout<<"\n\n";
    
       cout<<"What is the height of the cone? >>>"; cin>> h ; cout<<"\n\n";
    
       s = sqrt(r * r + h * h);
    
       cout<<"The area of the base is: "<< 3.14159265358979323846 * (r * r) <<"\n\n";
    
       cout<<"The surface area of the triangle is: "<< 3.14159265358979323846 * r * (r+s) <<"\n\n";
    
       cout<<"The height of the sloped side is: "<< s <<"\n\n";
    
       cout<<"The volume of the cone is: "<< 3.14159265358979323846 * r * r * h/3 <<"\n\n"; 
       break;
       
  case 4:
       cout<<"Press \"Enter\" to close...\n";
    break;
    
  default:
    cout<<"Error, bad input, quitting\n";
    break;
  }
  cout<<"Press \"Enter\" to continue on.\n\n";
  cin.get();
  cin.get();
  }
}

-----Edit-----
Don't you just love how I took pi to 21 digits? lol Overkill much?