Overload Function Error Messages

Question

This program is supposed to check if a string is a palindrome by using only one variable and any number of stacks. It is giving me a number of error messages relating to overloaded functions, but I don't see where I overloaded it. Or did I declare the stacks wrong? I commented in the error messages after the lines of code they referred to. Thanks!

int main()
{
    stack <char> stackA;
    stack <char> stackB;
    stack <char> stackC;

    char avariable;
    cout << "Enter a string: ";
    avariable = cin.get();
    while(avariable != '\n')
    {
        if(avariable != ' ')
        {

            stackA.push(avariable);
            stackB.push(avariable);
            avariable = cin.get();
        }}

    stackC.push('$');

    while(!stackB.empty())
    {
        avariable = stackB.top; //error, cannot resolve overloaded function 'top' based on conversion to type 'char'
        stackC.push(avariable);
        stackB.pop; //statement cannot resolve address of overloaded function
    }

    avariable = '$';
    stackC.push('$');

    while(!stackA.empty())
    {
        if(avariable == stackC.top) //invalid operands of type 'char' and <unresolved overloaded function type>' to binary 'operator=='
        {
            avariable = stackA.top; //cannot resolve overloaded function 'top' based on conversion to type 'char'
            stackA.pop; //cannot resolve address of overloaded function 
            stackC.pop; //cannot resolve address of overloaded function 
        }
        else
        {
            cout << "The string of characters entered is not a palindrome." << endl;
        }
    }

    if (stackC.top == '$') //invalid operands of type 'char' and <unresolved overloaded function type>' to binary 'operator=='
    {
        cout <<"The string of characters entered is a palindrome." << endl;
    }

}

Shoe · Accepted Answer · 2014-01-22T19:46:58.493

2

The std::stack template class only has member functions top() and pop() defined. You are trying to access them as public member objects, instead. Function calls require the use of parenthesis even if no arguments are passed.

Just replace all the occurrences of .top and .pop to .top() and .pop() respectively, and your program should at least compile.

Also please get used to the std:: prefix instead of including the entire std namespace with using namespace std. It will save you potential troubles, in the long run.

edited Jan 22 '14 at 19:46

answered Jan 22 '14 at 19:41

Shoe

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Why do you say that using std:: for each instance is better? I was told the opposite by a professor, though I don't remember him explaining the benefits of it. – Neko Jan 22 '14 at 20:03
Thanks! I guess I should have looked it up before I asked. – Neko Jan 22 '14 at 20:10
@Neko, don't worry. As long as you don't post a duplicate question, it's ok to ask. – Shoe Jan 22 '14 at 20:12

score 1 · Answer 2 · answered Jan 22 '14 at 19:40

1

To call a function, you need parentheses:

stackB.top()
stackB.pop()

As both top and pop take no arguments, the parentheses are empty but still required.

This is no different to where you have done stackA.empty() or cin.get() for example.

answered Jan 22 '14 at 19:40

Joseph Mansfield

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Overload Function Error Messages

2 Answers2