freopen

/* freopen example: redirecting stdout */
#include <stdio.h>
 
int main ()
{
  freopen ("myfile.txt","w",stdout);
  printf ("This sentence is redirected to a file.");
  fclose (stdout); //По идее здесь тоже надо написать freopen(консоль,"a",stdout);
  printf("This sentence must be redirected back to console");   //добавлено мною, ничего не выводит(ни в файл, ни в консоль)
  return 0;
}

/* freopen example: redirecting stdout */
#include <stdio.h>
 
int main ()
{
  freopen ("myfile.txt","w",stdout);
  printf ("This sentence is redirected to a file.");
  fclose (stdout);
  freopen("CON","w",stdout);
  printf("This sentence must be redirected back to console");
  return 0;
}

freopen("CON","w",stdout);

#include <iostream>
#include <fstream>
 
int main()
{
    std::ofstream ofs("our_file.txt");
    std::streambuf* our_buffer = std::cout.rdbuf(ofs.rdbuf());
    std::cout << "Write to file\n";
    std::cout.rdbuf(our_buffer);
    std::cout << "Write to stdout\n";
    ofs.close();
}

ofstream outfile("fdata.txt");
outfile << '\n'
        << temp1
        << ' '  
        << temp2;