// Basically the function reads text from a file (file) and updates a string (captionText) by reference, using captionWidth as a parameter.. captionLines is also updated for other reasons..
 
#include <fstream>
#include <string>
#include <iostream>
 
void get_caption (std::fstream& file,
                  std::string& captionText,
                  unsigned captionWidth,
                  unsigned& captionLines)
{
    std::string eachLine;
    while (!file.eof())
    {
        std::getline(std::cin,eachLine);
        captionText += eachLine;
    }
    unsigned charsPerLine = (12/100) * captionWidth; // 12 chars fit under 100 pixels of image
    for (int i=charsPerLine; i<captionText.size(); i+=charsPerLine)
    {
        if (i >= captionText.size())
            return;
        while (captionText.at(i) != ' ' && captionText.at(i) != '\n')
            i--;
        captionText.at(i) = '\n';
        captionLines++;
    }
    return;
}

while( ! EOF )
{
           read eachLine from file
                 if( eachLine.size() > allowed_caption_size )
                                output_string += chopOff( eachLine ) + '\n' ;
                 else
                                output_string += eachLine + '\n' ;
}
//PS: remove extra '\n' at the end if required

void get_caption (fstream& file,
                  vector<string>& captionTextsVec,
                  unsigned captionWidth)
//PS: captionLines not needed as captionTextsVec.size() would give you that