How to read input when debugging in C++ in Visual Studio Code? [duplicate]

Question

This question already has answers here:

How can I write to the standard input of a C/C++ program I'm running/debugging in VS Code with the C/C++ extension? (8 answers)

Closed 1 year ago.

I'm using VSCode for debugging my CPP program in MacOSX.

I've 2 programs.

Program1

int main(){
 string a;
 a = "a";
 a += 'b';
 cout<<a<<endl;
 return 0;
}

Program2

int main(){
 string a;
 cin>>a;
 a += 'b'
 cout<<a;
 return 0;
}

In program1 I'm directly assigning the string a and when I debug the program in VSCode by first compiling it in terminal using :

g++ -g filename.cpp

and then selecting the Starting Debugging option in the Debugging menu. I'm able to see the state of the string a variable by moving forward in breakpoints.

The VARIABLES section shows the state of different variables and the CALL STACK show the stack frame.

But, for program2, when I go past the breakpoint of the cin>>a;, the contents of VARIABLES and of CALL STACK get cleared up.

Here are the contents of the launch.json file:

{
 "version": "0.2.0",
 "configurations": [ 
 {
 "name": "(lldb) Launch",
 "type": "cppdbg",
 "request": "launch",
 "program": "${workspaceFolder}/a.out",
 "args": [],
 "stopAtEntry": false,
 "cwd": "${workspaceFolder}",
 "environment": [],
 "externalConsole": false,
 "MIMode": "lldb"
 }
 ]
}

How can I get user-input and move forward to debug my code?

• NathanOliver: Not sure if it is the same for VSCode but in VS when you step over input in the debugger you can switch over to the console window and type in the input, press enter, and then go back to stepping through the code.
• Vlad from Moscow: @Jos Place a breekpoint to this statement a += 'b'
• asn: @VladfromMoscow Yes, I did that and the debugging pauses there. Where can I provide my inputs?
• Vlad from Moscow: @Jos Use the console window.
• asn: @rioV8 Unfortunately, that's NOT.

Answer 1

As stated in Here

if you enable "externalConsole":true in the launch.json then you will get a pop up console window that you can type in.

• Orestis Kapar: This does not seem to work with piping input from stdin like ./program < input.txt. Is there an alternative for that?
• Orestis Kapar: Turns out that it works if you put "<" and "input.txt" as separate arguments.
• jozxyqk: sadly this isn't an option for me. the debugger never launches. same as stackoverflow.com/questions/53108690/…
• Scott Prive: This is outdated information. I just installed Mac CodeLLDB and it is now a little easier, but there are still a few steps. Watch a video walk-through this worked for me: youtube.com/watch?v=wKjFVyDbSpA
• Kermito: I don't know when they update that, but now to get the same result the configuration is : "console": "integratedTerminal"

Answer 2

To debug with inputs, you can edit the arg section as shown below:

"program": "${workspaceFolder}/main",
"args": ["<", "input_file.in"]

The example above should be the same as: ./main < input_file.in

Answer 3

1. Install extension CodeLLDB

2. Add new configuration CodeLLDB: Launch

   Add new configuration

3. Set program property as "program": "${workspaceFolder}/${fileBasenameNoExtension}"

4. (optional) Rebuild code

5. Chose created Launch config in VS Debug tab. And start it!

   Chose created Launch config in VS Debug tab

Profit! Demo Video manual

• xyistar Galaxy: You help me a lot , thank you !

Answer 4

I hope this helps anyone who comes around here:

by (1) setting "externalConsole" to true and (2) checking (enabling) "Run In Terminal" in Code-Runner Extension configuration, you can plug-in your input to your code by typing the input on the external console, that would pop up when you run your code.

Answer 5

simply:-
step1. click on small gear-icon of debugger window.
step2. make "true" to this ["externalConsole": false,] in launch.json file.
step3. and just restart your debugger.

Answer 6

If the code you are debugging requires user input, set external Console to true. after entering input, avoid clicking "x" to close the external Console. Instead, click "-" to minimise the window. Then keep hitting f10 or f11 to continue debugging.

• Neer Patel: I tried this, What my VS code does is, it opens entirely new terminal instance ( rather using VS-code terminal , which opens in bottom part ) . I was able to do debugging, but lot of switching between windows. Any idea how to solve it ?
• Saqib Ayoub: There is no need to switch windows. Simply divide the computer screen in half, keeping the VS code and the debugging window on either side. And keep debugging

Answer 7

I also encountered the same problem, my solution was to replace cygwin's gdb and g ++ with mingw64's.

• Kuznetsov-M: Can you please explain what settings you have done?

Answer 8

In my case this was a two-step process.

1. Enable externalConsole: true, as described in other responses.
2. Let VS code control the terminal.

Answer 9

externalConsole: true, allows me to type input in the external console but the redirection method "args":["<","in.txt"], does NOT

Using: VSCode 1.80.2 with C/C++ Extension from Microsoft v1.16.3 and Clang Apple clang version 14.0.3 (clang-1403022.14.1) Target: x86_64-apple-darwin22.6.0 Thread model: posix

macOS: Ventura 13.5 (22G74)

• Vladlen: redirection symbol "<" is processed by command shell (sh, bash, cmd.exe etc), but debugger runs your program and attach to it directly. If you like to process redirection, you can edit comand line and add shell into it.