Writing ALL program output to a txt file in C++

Question

I need to write all my program output to a text file. I believe it\'s done this way,

sOutFile << stdout;

where sOutFile is the ofstr

Answer 1

Then you cannot use std::cout anywhere else to print stuff from your program. Change std::cout to a std::ostream and then pass your file or std::cout as required.

Answer 2

If your program already uses cout/printf and you want to send EVERYTHING you currently output to a file, you could simply redirect stdout to point to a file before your existing calls: http://support.microsoft.com/kb/58667

Relevant Code:

freopen( "file.txt", "w", stdout );
cout << "hello file world\n"; // goes to file.txt
freopen("CON", "w", stdout);
printf("Hello again, console\n"); // redirected back to the console

Alternatively if you just want Some things to be printed to a file, you just want a regular file output stream: http://www.cplusplus.com/doc/tutorial/files.html

Relevant Code:

ofstream myfile;
myfile.open("file.txt");
myfile << "Hello file world.\n";
printf("Hello console.\n");
myfile.close();

EDIT to aggregate answers from John T and Brian Bondy:
Finally, if you're running it from the commandline, you can just redirect the output as everyone else mentioned by using the redirect operator ">" or append ">>":

myProg > stdout.txt 2> stderr.txt

Answer 3

sOutFile << stdout;

in C "stdout" is defined as a FILE* variable. It's just a pointer. Outputing it to a file just writes the value of the pointer, in your case: 0x77c5fca0 to the file.

If you want to direct your output to a file either write it the a file in the first place or redirect the output of your program to a file using the command line.

Answer 4

This is a duplicate of: this question

You can redirect stdout, stderr and stdin using std::freopen.

From the above link:

/* freopen example: redirecting stdout */
#include <stdio.h>

int main ()
{
  freopen ("myfile.txt","w",stdout);
  printf ("This sentence is redirected to a file.");
  fclose (stdout);
  return 0;
}

You can also run your program via command prompt like so:

a.exe > stdout.txt 2> stderr.txt

Answer 5

If you want all output in a text file you don't need to code anything extra.

from the command line:

program > output.txt

If you only wish to redirect certain output you can use ostream as dirkgently suggested.