/* string processing program - less modular */
#include <iostream>
#include <fstream>
#include <string>
using namespace std;

//function prototypes
void change(string &line);

int main()
{
    string line;

    // open input file
    ifstream infile("c:\\bc\\CISC1110\\pgms\\chapter8\\myinput.txt"); //comment-out for debugging
    //ifstream infile("con");                     //un-comment for debugging

    // open output file
    //ofstream outfile("c:\\bc\\CISC1110\\pgms\\chapter8\\myoutput.txt"); //comment-out for debugging
    ofstream outfile("con");                    //un-comment for debugging

    while (getline(infile, line))
    {
        outfile << line << endl;                //output old line
        change(line);                           //make changes
        outfile << line << endl;                //output revised line
    }

    infile.close();                             //close input file
    outfile.close();                            //close output file

//  system("pause");                            //un-comment when using DevC++
    return 0;
}

/* Function change()
 * Input:
 *  line - a reference to the string to be processed
 * Process:
 *  repeatedly call getchanges() to get a new set of
 *  replacement strings (oldstr & newstr), until there
 *  are no more sets of changes.
 * Output:
 *  line - the processed string
 */
void change(string &line)
{
    string oldstr, newstr;
    string::size_type pos;

    // open changes file
    ifstream changesfile("c:\\bc\\CISC1110\\pgms\\chapter8\\mychanges.txt"); //comment-out for debugging
    //ifstream changesfile("con");                            //un-comment for debugging

    while (getline(changesfile, oldstr))                    //read oldstr
    {
        getline(changesfile, newstr);                       //read newstr
        pos = line.find(oldstr, 0);                         //search for oldstr
        while (pos != line.npos)                            //if oldstr found
        {
            line.replace(pos, oldstr.length(), newstr);     //replace oldstr with newstr
            pos = line.find(oldstr, pos+newstr.length());   //search for oldstr
        }
    }
    changesfile.close();
    return;
}