I installed minGW and the eclipse CDT, and the console keeps doing something weird. The code of the program is
using namespace std;
#include <iostream>
int main() {
cout << "Hello, windows (8, c++)" << endl;
//system("PAUSE");
return 0;
}
You all know it, its the Hello World program. Now when I run this the Eclipse console displays some stuff about building, and then goes blank. And when I navigate to the HelloWorldProgram.exe in the explorer and run it, a windows flashes up and displays "hello world", but then immediately closes. When I do this on Mac OSX there's no problem, and the windows stays up until I decide to close it. Now I know there's a command
system("PAUSE") //I dont know what I need to import to use this. Could you tell me that too?
Which will give me more or less the same effect, but I'd like to know why Windows does it differently from OSX, and what I can do to fix it (bc this annoys the crap out of me).
Looking forward to your replies!
This happens on Windows because this is just the behavior of the Windows console. You'll have to open up the console manually and then running your program through the console you've opened if you don't want the window to close automatically once the program has executed.
You may want to take a look at these:
What is the Best Practice for Combating the Console Closing Issue?
https://superuser.com/questions/186562/how-can-i-keep-the-terminal-open
Don't use system("pause"), it's wrong for a multitude of reasons (read more about it here).
Put cin.get() before return and the window will stay open until you press enter.
If you want to just run your console program, you should open a console, and run it.
Apparently, the OSX version of Eclipse is configured to open a console, and run the program, and not close it. Maybe you can configure the Win version so, too.
You shouldn't meddle with your program to behave differently on another platform, instead wrap it into something that 'adapts' the behaviour.
Probably, you can tell eclipse to use "cmd /c 'yourprogram.exe && pause'", to open a command window and have it execute your program and then pause.
Just add getch(); before return, and add #include <conio.h>.
Related
On Windows I normally create a Windows Desktop Application, this is because console applications display a brief black box on the screen.
I am using CodeBlocks on Linux Mint, how could I do the equivalent of the above but on Linux?
I do not want to hide the terminal window after it has been displayed.
Linux does not have the same "subsystem" concept as windows: there is no difference or separation between console and desktop applications. When you start an application on Linux, it will not open a console window, unless the programmer explicitly programmed it to open one.
If the application writes anything to stdout or stderr, what happens with that depends on how exactly the application got started. By default, the application inherits the stdout and stderr of its parent process. If the application is being started from a terminal, the output will be visible on the terminal. If the application was started by the desktop environment from a menu entry, the output may go to a log file or it may be lost.
If you see a terminal window open when you run your program from the IDE, that's something that the IDE is doing for you, it's not your application. If it bothers your, I would think that the IDE has a way to disable this behavior in settings.
Look into QT. It is a GUI framework that works on Linux.
You can write your code without creating a main window (or maybe you have to have a main window but it can be always hidden... it's been a while since I've used it).
Be aware though, that you may run into usability issues with this type of design... the user has no way of knowing if your app was launched or if it succeeded, when it's completed, etc.
The simple way is to use (e.g.) xterm [or gnome-terminal] to get a terminal window.
Then, invoke your program from the shell [manually]:
/path_to_my_program
You may be able to configure codeblocks to do this for you.
Or, you could add some code that holds the default window open:
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/wait.h>
int main()
{
pid_t pid = fork();
if (pid != 0) {
waitpid(pid,NULL,0);
while (1) sleep(1);
}
long double n;
n=5;
printf("n= %Lf\n",n);
return 0;
}
UPDATE:
The invocation command can be controlled from: Settings -> Environment -> General Settings
The default is to invoke in an xterm sub-window [popup]. You may be able to change the settings to (re)use an existing [terminal] window.
Note that [a codeblocks program] cb_console_runner is used. You may be able to replace this with something more to your liking.
I do not want a GUI nor a terminal popup...
You'll need some sort of terminal to run the command in. This could be a script that diverts stdin/stdout/stderr as appropriate [and suppresses the invocation of a sub-window], so you'll have to experiment a bit.
As I mentioned above, you can just open a terminal window outside of codeblocks and then run the command manually inside it. Technically, this is not a popup. But, you lose the [automatic] debugger invocation.
I have a very simple C++ program with a very simple project setup, but when I run the program I get no output. If I run the program in debug mode, it works perfectly. I am using Eclipse Kepler CDT 32 bit on windows with MinGW. I am somewhat new to eclipse, so it's probably something I did wrong.
The program is:
#include <fstream>
#include <iostream>
#include <string>
using namespace std;
ofstream outfile("testdata.txt");
int main()
{
outfile << "Program Start\n";
cout << "Program Start\n";
return 0;
}
Help!
If the problem is that the program quickly opens and then closes before you can see the output on the screen, then you can just run your program from any shell (CMD on Windows, bash on Linux, etc.). That way, it won't exit once your program ends and you can see the results.
Make sure also that you flush/close your ofstream before your program exits.
The problem is rather not releted to c++ itself. You should check if via "cmd" typying it in "launch menu" after you click start. Find the path of your program, then run it.
For the very beginning it is recommended to spend a few hours with terminal(cmd). To know how things works. After that you will be independent - you will be able to write the code in any IDE. Also simple trick to make it working is to use std::cin.get() . It is prefered to system("pause").
You open the testdata.txt file using the relative path.
And the created file may be created in the project binary output path, where the executable located in.
You can use everything software to check whether a file is created and its created path.
everything
For example, you can type your output file name testdata.txt into everything software to see where output file created.And check if the testdata.txt created in a wrong path or directory.
I have a problem, when I try to open my Hello World.exe file (that I created by following a tutorial). It immediately closes without giving me the chance to read or see if I have done everything correctly.
As you can see, I need help on how to keep it open, without instantly closing.
You can either put a break point before the end of main or try the following:
int main()
{
//...
std::cin.get();
return 0;
}
It is going to wait for you to press some key to exit the console.
EDIT: It is better to add break point which do not change existing code.
In console applications there are a couple of things you can do to stop the window from closing on you such as using system("pause") (not so recommended though), getch(), std::cin >> x etc at the end of the application.
Another option is to start a cmd window, cd to the location of the exe and run it like any other console application is meant to be ran, that way it wont just close on you, it'll simply exit.
In VS2017, you can specify that the executable is a Console app, not a Windows app. This makes your application run in a "Microsoft Visual Studio Debug Console", with "Press Any Key To Close This Window" appearing at the end of the console output:
Right click the project to bring up Properties.
Linker > System > Subsystem > Select "Console".
Press Apply before closing.
I just installed c/c++ development tools for my eclipse and everything is working except no text is being printed in the console when I run the hello world program, but I receive no errors. I'm really stumped, anyone know why this is?
Edit:
Ok I realized if that debug it, it works correctly, but not if I run it, any ideas there?
Are you using a 64-bit version of Eclipse? If so, that might be your problem. The 64-bit version doesn't do console output. sigh Try downgrading to the 32-bit version.
On SO, check this question.
On the Eclipse forums, check this thread.
Does a window pop up then disappear? It could be printing it in console then closing as soon as it hits the end of the code...
try to make your code like this:
#include <iostream>
#include <conio.h>
using namespase std;
int main()
{
cout << "helllo, world" << endl;
getch();
return 0;
}
You must set the environment so the eclipse can find the c++ compiler.
Go to Computer and right click Properties -> advanced system settings -> enviroment variables.
Scroll down in system variables and find the path (it is named so). Press edit and append in the path the value C:\MinGW\bin;C:\MinGW\msys\1.0\bin;. You will have something like C:\MinGW\bin;C:\MinGW\msys\1.0\bin;C:\programfiles........
Then start again the eclipse the problem should have been solved.
I'm totally new to Ubuntu and C++. Anyway, I have PHP experience.
I just created very simple application...
#include <iostream>
int main() {
std::cout << "Hello, world!";
return false;
}
Then compiled it....
g++ hello-world.cpp -o hello-world
But I can't open it with double-click on it, like I did on Windows 7. Only way to get that text printed is to do command...
./hello-world
Is it possible to open compiled file using simple double-click and then get that text somehow printed?
The program you wrote is a console application. In most Linux GUIs, by default if you open a console program from the GUI, the console output will not be displayed. You can either configure the GUI to open a terminal, or you can manually open a terminal and run it yourself.
When doing development, I highly recommend manually running the program - with using the GUI's automatic terminal window opening mode, the terminal will close as soon as the program terminates; so if the program crashes, the message will be lost. Manually opening a terminal ensures it sticks around after termination, so you can read the program's last messages before terminating.