undefined reference to add(int x, int y) ???

[reiki222]

undefined reference while trying to forward declear a function (add int x , int y ).... please help , thanks
compiler is dev c++

#include <cstdlib>
#include <iostream>
#include "conio.h"
#include "math.h"

   int add (int x, int y);
float adx(float a ,float b)
{
return a+b;
}
double sqt(float c,float d)
{
  return pow(c,d);
}
int main(int argc, char *argv[])
{
 
    float a;
    float c;
    float d;
    float b;
    
    using namespace std;
    
    cout << "two values" <<  add(3,4) << endl;
    
    cout << "enter value of a" << endl;
    cin >> a;
    
    cout << "enter value of b" << endl;
    cin >> b;
    
    cout << "enter another value" << endl;
    cin >> c;
    
    cout << "enter another value" << endl;
    cin >> d;
    
    cout << "square root of last two values is" << sqt(c,d) << endl;
    
    cout << "sum of first two values is" << adx(a,b) << endl;
    cin.get();
    
    cin.get();
    return EXIT_SUCCESS;
}

[vlad from moscow]

Where is there the function definition?! Or you think the compiler shall invent it itself instead of you?

[Peter87]

The linker can't find the definition of add. Where is it?

[reiki222]

is it the " int add (int x, int y);" line?

[Peter87]

No that's a declaration. The definition is where you write what the function should do.

[reiki222]

...... how to change it

[vlad from moscow]

What are you going to change?! You have to define this function. Nobody knows what it should do except you.

[reiki222]

it adds 3 and 4

[vlad from moscow]

Maybe. I do not know beacuse neither me nor the compiler see the function definition.
Stop bla, bla, bla. Define the function!

[ne555]

look at lines 7-10 to how define a function

[reiki222]

thanks , it finally worked