C++ Tokenize a string with spaces and quotes

No library is needed. An iteration can do the task ( if it is as simple as you describe).

string str = "add string \"this is a string with space!\"";

for( size_t i=0; i<str.length(); i++){

    char c = str[i];
    if( c == ' ' ){
        cout << endl;
    }else if(c == '\"' ){
        i++;
        while( str[i] != '\"' ){ cout << str[i]; i++; }
    }else{
        cout << c;
    }
}

that outputs

add
string
this is a string with space!

I wonder why this simple and C++ style solution is not presented here. It's based on fact that if we first split string by \", then each even chunk is "inside" quotes, and each odd chunk should be additionally splitted by whitespaces.

No possibility for out_of_range or anything else.

unsigned counter = 0;
std::string segment;
std::stringstream stream_input(input);
while(std::getline(stream_input, segment, '\"'))
{
    ++counter;
    if (counter % 2 == 0)
    {
        if (!segment.empty())
            std::cout << segment << std::endl;
    }
    else
    {
        std::stringstream stream_segment(segment);
        while(std::getline(stream_segment, segment, ' '))
            if (!segment.empty())
                std::cout << segment << std::endl;
    }
}