Replacing Number within a text File

[phh]

Hey everyone.

I have a text file (Actually a .BFR file that I just renamed to .txt) that I need to update values in. I already created my C++ program that will open that file, search the file for whatever value I want to replace. And what lines those values occur on.

However, I can't seem to figure out how to actually replace those numbers with another one.

[phh]

#include <cstdlib> 
#include <iostream>
#include <string>
#include <fstream>
#include <cstring>

using namespace std;

int main()
{   
    ifstream in_stream;           
    string filein, search, str, replace; 
    int lines = 0, 
    char ch;
      
    cout << "Filename:\n";  
    cin >> filein;                            
    in_stream.open (filein.c_str(), ios::in | ios::binary); 
    
    
    //FIND
    cout << "Number to find replace: " <<endl; 
    cin >> search;

    while (!in_stream.eof())  
    {getline(in_stream, str); 
     lines++;                 
     if ((str.find(search, 0)) != string::npos) 
        {
        cout << "found at line " << lines << endl; 
        }
    }
    
    in_stream.seekg (0, ios::beg);

So this finds the numbers I'm looking for, then spits out the lines that they are on. This works as I confirmed with Notepad++.

[TheDestroyer]

http://www.daniweb.com/software-development/cpp/threads/166889/changing-a-line-in-file

[phh]

That talks about finding and replacing a line though. My numbers are within a line. How would I find the position of them within the line to replace them.

For example, my line is something like this:

#blahblah  "A|B|32190|32190||BOOGIE||HAHA|M||||||NOPE|||||||||||
#DSFSD "O|1|32190|SDFLSDHJKF|SFSDF|SD|||SDFSD 

So basically I have about 500 numbers like that in sequence. And I want this program to search for 32190, increment it by 300, replace the 32190 with 32490.

Make sense?

[TheDestroyer]

You can read the whole line and then use string manipulation to replace whatever you want. I think reading and writing a single text line from a file is nothing for now-a-days' computers, right?

[phh]

I'm still super confused on how to replace that number, and then write to the same file? Is that possible? Or do I have to delete that file, and then write a new one with the same name?

[phh]

Can someone point me in the right direction?

Thanks.