Question

Error:
error C2678: binary ‘==’ : no operator found which takes a left-hand operand of type ‘const entry’ (or there is no acceptable conversion)

The function:

template <class T, int maxSize> int indexList<T, maxSize>::search(const T& target) const {     for (int i = 0; i < maxSize; i++)           if (elements[i] == target)   //ERROR???             return i;       // target found at position i      // target not found     return -1; } 

indexList.h
indexList.cpp

Is this suppose to be an overloaded operator? Being a template class I am not sure I understand the error?

Solution- The overload function in the class now declared const:

//Operators bool entry::operator == (const entry& dE)  const <-- {     return (name ==dE.name);  } 

Answer 1

Start by reading the error text exactly as it is:

binary ‘==’ : no operator found which takes a left-hand operand of type ‘const entry’

It means it can’t find any == operator that accepts an entry type as its left operand. This code isn’t valid:

entry const e; if (e == foo) 

You’ve showed us the code for your list class, but that’s not what the error is about. The error is about a lack of operators for the entry type, whatever that is. Either give the class an operator== function, or declare a standalone operator== function that accepts a const entry& as its first parameter.

struct entry {   bool operator==(const entry& other) const; }; // or bool operator==(const entry& lhs, const entry& rhs); 

I think the latter is the preferred style.