A simple find and replace for C++

replaceString

std::string& replaceString(std::string& newString, const std::string& searchString, const std::string& replaceString, const bool& multipleReplace)
{
    size_t index = newString.find(searchString);
    if(multipleReplace)
    {
        while(index != std::string::npos)
        {
            // replace
            newString.replace(index, searchString.size(), replaceString);
            // start searching from the end of the replaceString, such that the replaceString will never be part of the search
            index = newString.find(searchString, index + replaceString.size());
        }
    }
    else
    {
        if(index != std::string::npos)
        {
            newString.replace(index, searchString.size(), replaceString);
        }
    }
    return newString;
}