Redirecting stdout to a file in C through code

I am outputting to stdout. How can I redirect that to a new file through code? While we run the program we can redirect like ./sample > test.txt. How can I do this when executing t开发者_如何学Pythonhe sample program itself ? (C programming)

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You probably want to use freopen.

Example from reference:

#include <stdio.h>
...
FILE *fp;
...
fp = freopen ("/tmp/logfile", "a+", stdout);

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Use freopen().

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Use dup2() system call and redirect the output to a file.