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

Question

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?

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. — NathanOliver, Aug 14 '19 at 12:37
@VladfromMoscow Yes, I did that and the debugging pauses there. Where can I provide my inputs? — asn, Aug 14 '19 at 12:40
@VladfromMoscow Is that the same as `Terminal` OR `Debug Console`? I mean, where is that present? — asn, Aug 14 '19 at 12:42
Do I need to run my program? I guess so. Nope running doesn't help. — asn, Aug 14 '19 at 12:44
The terminal just shows the command that I had executed before debugging ie - `Ajays-Air:cppnew ajay$ g++ -g d.cpp` — asn, Aug 14 '19 at 12:45
Where is the location/window/panel that shows the output of `cout< — rioV8, Aug 14 '19 at 13:48
That should be the location where to enter the program keyboard input — rioV8, Aug 14 '19 at 18:29

score 34 · Accepted Answer · answered Aug 14 '19 at 16:00

34

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.

answered Aug 14 '19 at 16:00

asn

2,408
5
23
37

1

This does not seem to work with piping input from stdin like `./program < input.txt`. Is there an alternative for that? – Orestis Kapar Feb 23 '20 at 11:28
3

Turns out that it works if you put "<" and "input.txt" as separate arguments. – Orestis Kapar Apr 15 '20 at 23:18
sadly this isn't an option for me. the debugger never launches. same as https://stackoverflow.com/questions/53108690/visual-studio-code-c-debugger-doesnt-start – jozxyqk Mar 18 '21 at 19:19
2

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: https://www.youtube.com/watch?v=wKjFVyDbSpA – Scott Prive Jun 17 '22 at 15:28

score 9 · Answer 2 · answered Mar 31 '20 at 01:40

9

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

answered Mar 31 '20 at 01:40

Joseph Pena

167
2
8

score 3 · Answer 3 · answered Jul 19 '22 at 23:03

Install extension CodeLLDB
Add new configuration CodeLLDB: Launch
Set program property as "program": "${workspaceFolder}/${fileBasenameNoExtension}"
(optional) Rebuild code
Chose created Launch config in VS Debug tab. And start it!

Profit! Video manual

score 2 · Answer 4 · edited Dec 17 '19 at 18:39

2

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.

edited Dec 17 '19 at 18:39

ϹοδεMεδιϲ

2,790
3
33
54

answered Dec 17 '19 at 16:13

tachyon

21
2

score 1 · Answer 5 · answered Feb 02 '21 at 11:20

1

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.

answered Feb 02 '21 at 11:20

Ajay jangid

711
9
9

score 0 · Answer 6 · answered Nov 27 '19 at 01:02

0

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

answered Nov 27 '19 at 01:02

傅继晗

927
1
8
14

Can you please explain what settings you have done? – Kuznetsov-M Jul 19 '22 at 22:23

score 0 · Answer 7 · answered Dec 03 '20 at 18:43

0

In my case this was a two-step process.

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

answered Dec 03 '20 at 18:43

Union find

7,759
13
60
111

score 0 · Answer 8 · edited Jan 29 '23 at 04:23

0

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.

edited Jan 29 '23 at 04:23

Nimantha

6,405
6
28
69

answered Jan 09 '23 at 05:59

Saqib Ayoub

1

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 ? – Neer Patel Jan 25 '23 at 09:04
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 – Saqib Ayoub Jan 26 '23 at 10:51

score 0 · Answer 9 · answered Aug 09 '23 at 21:34

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-1403.0.22.14.1) Target: x86_64-apple-darwin22.6.0 Thread model: posix

macOS: Ventura 13.5 (22G74)

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

9 Answers9

Linked