C++ String Compare

Question

I have 2 strings: in , which contains a link originally entered by the user (assume it to be "http://google.com/test"), and found , which has already been found by an extraneous part of this program.

The goal of this function is to compare the section of string between http:// and /test , ie: "google.com"

The problem I'm encountering is that the loop is not adding to the compare string, thus the later attempt to compare the 2 strings in the program at runtime.

bool isLinkExternal(string in, string found)
{
    string compare = "";
    bool isExternal = false;

    //Get domain of original link
    for (int i = 6; in[i] != '/'; i++)
    {
        compare += in[i];
    }

    system("pause");

    //Compare domains of original and found links
    if (found.compare(7,compare.length(),compare) != 0)
        isExternal = true;

    return isExternal;
}

The error:

An unhandled exception of type 'System.Runtime.InteropServices.SEHException' occurred in ParseLinks.exe

The line of code it points to:

if (found.compare(7,compare.length(),compare) == 0)

Fixed code (working):

bool isLinkExternal(string in, string found)
{
    const int len = found.length();
    int slashcount = 0;
    string comp;

    //Parse found link
    for (int i = 0; i != len; i++)
    {
        //Increment when slash found
        if (found[i] == '/')
        {
            slashcount++;
        }

        if (slashcount < 3)
        {
            comp += found[i];
        }
    }

    //Compare domains of original and found links
    if (in.compare(0,comp.length(),comp) == 0)
        return false;
    else
        return true;
}

Answer 1

(int i = 6; in[i] != '/'; i++)
{
    compare += in[i];
}

Did you mean this?

for (int i = 6; in[i] != '/'; i++)
{
    compare += in[i];
}

At present, your string does not have seven characters in it, so your compare is invalid. In fact, you will need to add some bounds checking there in any case.

Also, the exception text implies that you're actually writing C++/CLI, not C++. Am I right?

Answer 2

Does this work better:

for (int i = 7; in[i] != '/'; i++)
{
compare += in[i];
}