Question

I have the following class setup that trys mimicks a very basic stack.

template <class T>
class Stack{
    public:
        static const unsigned MAX_STACK_DEPTH =4;
        Stack();
        unsigned elements() const;
        Stack<T> & push(T &value);
        T pop();
        Stack<T> & show();
    private:
        unsigned element;
        T stack[MAX_STACK_DEPTH];
};

template <class T>
Stack<T>::Stack(){
    element=0;
}
/*Other class function definitions*/

My problem is that I’m getting the following error in main

1   IntelliSense: no instance of function template "calc" matches the argument list c:\users\nima\documents\visual studio 2010\projects\calcu\calcu\policalc.cpp    109 6   Calcu

Here is my main

int main(){
    bool run=true;
    while(run){
        if(calc(input()));
    }
}

here are the other two functions declarations

string input();
template <class T>
bool calc(string line);

Here is my calc function, It’s not finished.

template <class T>
bool calc(string line){
    static T Ans;
    istringstream sin(line);
    Stack stack;
    for(string token; sin>>token){
        T t;
        if(parse(t, token)){
            push(t);
        }else{
            if(token==operators[i]){
                switch(i){
                case 1:{

                       }
                }
            }
        }
    }
}

Answer 1

Your calc function is a function template with parameter T, but that parameter isn’t used by any of the function arguments – the only argument is defined as a string, regardless of what type T is.

Therefore, the compiler cannot defer T when you call calc like this:

calc(input())

You need to explicitly specify T, e.g.:

calc<int>(input())

(Of course, you should use whatever data type makes sense instead of int.)