change file at given position : file pointer « File Stream « C++ Tutorial






#include <iostream>    
#include <fstream>   
#include <stdlib.h>   
using namespace std;
main(int argc, char *argv[])   
{   
  if(argc!=3) {   
    cout << "Usage: CHANGE <filename> <byte>\n";   
    return 1;   
  }   
     
  fstream out(argv[1], ios::in|ios::out);   
  if(!out) {   
    cout << "Cannot open file";   
    return 1;   
  }   
     
  out.seekp(atoi(argv[2]), ios::beg);   
     
  out.put('X');   
  out.close();   
     
  return 0;   
}








12.6.file pointer
12.6.1.change file at given position
12.6.2.get file content at given position
12.6.3.Change a file at specific position
12.6.4.Check ofstream current marker position
12.6.5.move to position 2 in the stream and output a 0 in position 2
12.6.6.Tell the current position
12.6.7.seek and Skip
12.6.8.Test File Position
12.6.9.Seek 0 to reset the file pointer
12.6.10.seekg( ) moves the pointer offset number of characters from the specified origin
12.6.11.uses both seekp( ) and seekg( ) to reverse the first characters in a file.
12.6.12.Detecting EOF