Question

I’m trying to wrap the words of a given string and display it in a message box using SFML (<– this doesn’t matter ).

So, what I am trying to do is to insert a new line before a word that is greater than the width of the message box. Here’s the code:

string& message::word_wrap( string& msg , int w, int pt_size )
{
    int text_width = w;
    vector< string > lines;
    string temp ( msg );
    temp += " ";
    int n = 0, p = 0;

    while ( n != -1 )
    {
        string substr;
        n = temp.find( " ", p+1 );
        if ( (n * pt_size) >= text_width )
        {
            substr = temp.substr( 0, p );
            lines.push_back( substr );
            if ( n != -1 )
                temp = temp.substr( p+1, string::npos );
            p = 0;
        }

        else p = n;
    }

    string rtn;
    for ( int i = 0; i < lines.size(); i++ ) rtn += lines[i] + '\n';
    return rtn;
}

I use it in my class like this:

message::message( sf::RenderWindow& App, const string& msg, int w, int h ) : app(App)
{
    /* irrelevant code */

    string m = msg; // <--
    m = this->word_wrap( m, w, text.GetSize() ); // <--
    text.SetText(m);
}

There are two problems.

1. The algorithm wraps the words way before they exceed the width of
   the message box.

2. The last few words are skipped for some reason, when I use
   it like this:

   pro::message::display( App, "Hello World! Yada Yada Bla Bla Yda Yada Hehehe Hehe Hfmaf Heh last few words" );
   

It skips the last word, words :

Answer 1

The easy solution is to make a copy of the string, and replace the space with a newline when appropriate.

The problem you are having, is because when you find the last space where you should to a linebreak, you still have text after that that is not pushed into the vector. You need to check if there are more text after the loop, and add that as a separate line.