C++ class template undefined reference to function [duplicate]

Answer 1

Your class is named wrong. Your class is named cai where all your functions belong to a class named number: http://ideone.com/ZayX0c

One more thing.. you cannot have templates in the .cpp file. Template functions/defintions go in the header along with the class declaration. This is the reason for your undefined function error. Non-template functions go in the .cpp.

#include 
#include 

template 
class number {
public:
    T x;
    T y;

    number (int a, int b){
        x=a; y=b;}
    int add (T&);
    T greater ();
};

template 
int number::add (T& rezAdd){
    rezAdd = x+y;
    return 1;
}

template 
T number::greater (){
        return x>y? x : y;
}


int main (int argc, char **argv) {
    int aux;
    number c(3,5);

    c.add(aux);
    printf ("number added [%d]\n", c.add(aux));
    printf ("greater number: [%d]\n", c.greater());

    return 0;
}