Questions tagged [freopen]
freopen reopens a stream with a different file or mode.
freopen
104
questions
0
votes
0
answers
11
views
Console screen import/export error when using freopen
Can anyone tell me that when using freopen, sometimes when I call new functions using input and output commands on the console screen, it doesn't work? When running, it still works and still processes ...
0
votes
1
answer
141
views
Why does redirecting the output of assert() work when done using freopen() and stderr but not when redirecting the buffer of std::cerr normally?
I'd like to redirect the output that assert() creates when an assertion fails, so that it is written to a log file instead of the output window. I assumed assert() uses std::cerr to output but when ...
- 939
1
vote
1
answer
91
views
Bash redirect to stdin after freopen()
I'm encountering a limitation of bash input redirection that's preventing me from accomplishing a task, and I haven't been able to find a way to work around it so far. Essentially, I need to be able ...
- 133
-1
votes
1
answer
130
views
C++ - my program stops running `freopen` function from <cstdio>
In my main.cpp:
#include <cstdio>
#include "hashtable.h"
int main() {
printf("1hello");
freopen("2.txt", "w", stdout);
printf("2hello&...
- 65
-1
votes
1
answer
136
views
C++: freopen (and I/O) just refuses to work
Today I'm having issues with my code. It appears that I can not get anything from input (whether file or stdin) as well as unable to print (whether from file or stdout). My code can have a lot of ...
- 147
2
votes
1
answer
288
views
Why does reopening stdout to a newly-allocated console occasionally fail?
Consider this program:
#include <windows.h>
#include <stdio.h>
#pragma comment(linker, "/SUBSYSTEM:CONSOLE")
int main(void) {
if (!FreeConsole()) {
MessageBoxA(NULL,...
0
votes
2
answers
187
views
Console outputs gibberish code after re-redirecting stdout to CON
When I use C++ to invoke Python program output (By system command with parameters), it outputs gibberish code at the end of line. After that, I couldn't input any character (Include Backspace and ...
- 307
0
votes
1
answer
562
views
use freopen() and scanf() to read an int from file
I try to read an int from a file using freopen(). File in.txt simply have a number:1, but what I get in output is -858993460. My code is shown below:
#include <cstdio>
#pragma warning(disable:...
0
votes
2
answers
339
views
Dynamic file stream handling in C with freopen
I am trying to write a program that ideally accepts arguments that specify both a source file (to read from) and a destination file (to write to).
The program replaces specified characters in source ...
- 61
0
votes
1
answer
53
views
Debug & run result differ in simple c app that redirects stdout using freopen
I'm using linux manjaro. I have the following code (cons.c)
#include <stdio.h>
#include <stdlib.h>
int main()
{
FILE *f=freopen("/dev/null", "a", stdout); //...
- 741
0
votes
2
answers
419
views
Freopen not writing output after a function call
I was doing a programming question and was using freopen to redirect the streams. The problem I am facing is that the printf command is not printing on the output file after stdout redirection. I even ...
- 311
1
vote
1
answer
203
views
Extra output when writing to file using std::cout
I am trying to read data from a file in.txt, and after some computations, I am writing the output to out.txt
Why is there an extra 7 at the end of out.txt?
Contents of Solution class.
class Solution
{
...
- 322
1
vote
1
answer
665
views
Not getting output using freopen in c++ :-vs code showing
#include <iostream>
using namespace std;
int main() {
#ifdef ONLINE_JUDGE
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#...
- 11
0
votes
0
answers
121
views
cin doesn't work along with freopen in wsl windows
I am running this simple cpp code in wsl and it outputs infinite times.
The reason being when I take input into the variable t, it simply doesn't take, and it still has the garbage value initiated to ...
0
votes
1
answer
996
views
freopen() does not read / write to existing file, niether creates new file in vscode
I am trying to read input and output from two separate text files in C++.
Code(test.cpp):
#include<bits/stdc++.h>
using namespace std;
int main()
{
#ifndef ONLINE_JUDGE
freopen("...
- 11