This is not an acceptable way to strip whitespace from a string.

gistfile1.cpp

void RemoveWhitespace(cString &szString)
{
    // Remove leading whitespace
    size_t nFirstIndex = szString.find_first_not_of(_L(' '));
    if(nFirstIndex != cString::npos)
    {
        szString = szString.substr(nFirstIndex);
    }

    // Remove trailing newlines
    size_t nLastIndex = szString.find_last_not_of(_L('\n'));
    while(nLastIndex != szString.length()-1)
    {
        szString.erase(nLastIndex+1,1);
        nLastIndex = szString.find_last_not_of(_L('\n'));
    };
    // Tabs
    nLastIndex = szString.find_last_not_of(_L('\t'));
    while(nLastIndex != szString.length()-1)
    {
        szString.erase(nLastIndex+1,1);
        nLastIndex = szString.find_last_not_of(_L('\t'));
    };
    // Spaces
    nLastIndex = szString.find_last_not_of(_L(' '));
    while(nLastIndex != szString.length()-1)
    {
        szString.erase(nLastIndex+1,1);
        nLastIndex = szString.find_last_not_of(_L(' '));
    };
}

For what it's worth, this code is used to read INI-like text files, and what I actually did to fix it was to stop copying strings around. My replacement function just takes a pair of iterators ("start" inclusive, "end" exclusive) and modifies it to strip whitespace:

static bool iswhite(int ch)
{
    return ch == _L(' ') || ch == _L('\t') || ch == _L('\n');
}

template<typename T>
static void RemoveWhitespace(T& start, T& end)
{
    while (start < end && iswhite(*start))
        ++start;

    while (end > start && iswhite(*(end - 1)))
        --end;
}

The code still eventually copies the extracted values into strings, but there's no reason to be creating tons of temporary strings in the meantime. For what it's worth, this is from a program that spent a significant amount of its (loading) time in RemoveWhitespace and its immediate callers, doing extremely inefficient text file parsing.

It's probably not the topic, but C++ has a very elegant way of solving this problem. Here's how simple it is:

bool iswhite(int ch) 
{ 
    return ch == ' ' || ch == '\t' || ch == '\n';
}

void RemoveWhitespace(std::string &str)
{
    str.erase(std::remove_if(str.begin(), str.end(), iswhite), 
                  str.end());
}

@dariomanesku: Your code removes all whitespace, not just leading and trailing.

@Poita: Yes, that's exactly what it does, isn't that what's necessary? If not, I'm sorry, I haven't quite taken my time to look carefully at the code, I was just passing by. Also, then, the function name could be a little different.

What about all the other whitespace characters? This targets only a rather small subset. :)