Help with a function

[9hX8C542]

So I need to write a function that is described like this:

std::string capitalize(const std::string& str);

/// Returns a copy of the string centered in a string of length 'width'. /// Padding is done using the specified 'fillchar' (default is an ASCII space).
/// The original string is returned if 'width' is less than or equal to the /// string's length.
/// @example center("C++ is fun", 20, '*') becomes " *****C++ is fun*****"

Header and parameters need to stay the same.

std::string center(const std::string& str, size_t width,
    char fillchar)
{
    int size1 = 0;
    int size2 = 0;
    int strLength = str.length();
    string newOutput = "";

    if(strLength < width)
    {
        size1 = strLength - width;
        size2 = size1/2;

        newOutput.append(size2, fillchar);
        newOutput = newOutput + str;
        newOutput.append(size2, fillchar);

        return newOutput;

    }//if for string length
    else
        return str;
}//function to center 

When I try to compile I get the error:
terminate called after throwing an instance of 'std::length_error'
what(): basic_string::_M_replace_aux

Thanks for your time

[Repeater]

size2, when calculated on line 12, is a negative number.

Using the string::append function with a negative number as the first parameter is a bad idea.

[z05DSL3A]

You could also look at creating the new string the correct size prefilled with the fillchar and then replace the middle section with the old string.

Look at the std::string constructor and std::string.replace()

[9hX8C542]

Thanks both of you, I was having such a hard time, but I'm good now.