CODEWITHSUNDEEP
c++templatesarguments
polmonroig
polmonroig

Reputation: 1017

No instance of function template "max" matches the argument list argument types are (int, int)

I am just starting with c++ and I don't have a lot of knowledge about templates, I made a template function and I am recieving this error in Visual Studio:

//No instance of function template "max" matches the argument list argument types are (int, int) //C2664'T max(T &,T &)': cannot convert argument 1 from 'int' to 'int &' 

#include "stdafx.h"
#include <iostream>

using namespace std;


template <class T>
T max(T& t1, T& t2)
{
    return t1 < t2 ? t2 : t1;
}
int main()
{
cout << "The Max of 34 and 55 is " << max(34, 55) << endl;
}

The copiling error is found in the max of the cout

Thank you!

Upvotes: 3

Views: 5868

Answers (2)

Arthur Tacca
Arthur Tacca

Reputation: 9989

A non-const reference parameter must be backed by an actual variable (loosely speaking). So this would work:

template <class T>
T max(T& t1, T& t2)
{
    return t1 < t2 ? t2 : t1;
}
int main()
{
int i = 34, j = 55;
cout << "The Max of 34 and 55 is " << max(i, j) << endl;
}

However, a const reference parameter does not have this requirement. This is probably what you want:

template <class T>
T max(const T& t1, const T& t2)
{
    return t1 < t2 ? t2 : t1;
}
int main()
{
cout << "The Max of 34 and 55 is " << max(34, 55) << endl;
}

Upvotes: 6

Marcel Kirchhoff
Marcel Kirchhoff

Reputation: 108

Your function is expecting two l-value references, though, what you're passing are two r-values.

Either pass two variables or change the function signature to accept r-value references.

Upvotes: 3

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