Replace part of a string with another string

Question

Is it possible in C++ to replace part of a string with another string?

Basically, I would like to do this:

QString string(\"hello $name\");
string.re         


        

Answer 1

My own implementation, taking into account that string needs to be resized only once, then replace can happen.

template 
std::basic_string replaceAll(const std::basic_string& s, const T* from, const T* to)
{
    auto length = std::char_traits::length;
    size_t toLen = length(to), fromLen = length(from), delta = toLen - fromLen;
    bool pass = false;
    std::string ns = s;

    size_t newLen = ns.length();

    for (bool estimate : { true, false })
    {
        size_t pos = 0;

        for (; (pos = ns.find(from, pos)) != std::string::npos; pos++)
        {
            if (estimate)
            {
                newLen += delta;
                pos += fromLen;
            }
            else
            {
                ns.replace(pos, fromLen, to);
                pos += delta;
            }
        }

        if (estimate)
            ns.resize(newLen);
    }

    return ns;
}

Usage could be for example like this:

std::string dirSuite = replaceAll(replaceAll(relPath.parent_path().u8string(), "\\", "/"), ":", "");