How to use the debugger in visual studio code? - c++

Question

I am using Visual Studio Code for C++ coding on Ubuntu 18.04.
I found that for the debugging, I should always build an a.out file and then use the debugger. If I run the code directly by ctrl+alt+n then the code runs completely but it won't give me an a.out file.
Is there any way that I can automate this process?
I have also noticed that there is no build option available.
Here is the launch.json file:
{
// Use IntelliSense to learn about possible attributes.
// Hover to view descriptions of existing attributes.
// For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
"version": "0.2.0",
"configurations": [
{
"name": "g++ - Build and debug active file",
"type": "cppdbg",
"request": "launch",
"program": "${fileDirname}/${fileBasenameNoExtension}",
"args": [],
"stopAtEntry": false,
"cwd": "${workspaceFolder}",
"environment": [],
"externalConsole": false,
"MIMode": "gdb",
"setupCommands": [
{
"description": "Enable pretty-printing for gdb",
"text": "-enable-pretty-printing",
"ignoreFailures": true
}
],
"preLaunchTask": "g++ build active file",
"miDebuggerPath": "/usr/bin/gdb"
}
]
}

Answer 1

You could create custom build+launch task for running your C++ code through a debugger.
Let's say we have this sample code:
#include <iostream>
#include <vector>
using namespace std;
int main()
{
cout << "Hello World!" << endl;
vector<int> numbers{ 10, 20, 30 };
for (int n : numbers)
{
cout << n << endl;
}
}
First, make sure to have Microsoft's C++ extension installed.
Next, create a custom build task.
This tells VS Code how to compile your code.
Open the Command Palette
Select Tasks: Configure Task
Select C/C++: g++: build active file
You can other compilers that are available on your system
That would create or open an existing .vscode/tasks.json file
Configure it
{
"type": "shell",
"label": "build-my-app",
"command": "/usr/bin/g++",
"args": [
"-g",
"-std=c++11",
"${workspaceFolder}/path/to/test.cpp",
"-o",
"${workspaceFolder}/path/to/test.out"
],
"options": {
"cwd": "/usr/bin"
},
"problemMatcher": [
"$gcc"
],
"group": "build"
}
Set label to uniquely name your custom task
Set the compile flags like -g, -std=xxx, -l<lib>, -I<header>
Set the output filename instead of a.out
Next, create a custom launch task.
This tells VS Code how to run your code through the debugger.
Open the Command Palette
Select Debug: Open launch.json
That would create or open an existing .vscode/launch.json file
Configure it
{
"name": "run-my-app",
"type": "cppdbg",
"request": "launch",
"program": "${workspaceFolder}/path/to/test.out",
"preLaunchTask": "build-my-app",
"args": [],
"stopAtEntry": false,
"cwd": "${workspaceFolder}",
"environment": [],
"externalConsole": false,
"MIMode": "lldb"
}
Set name to uniquely name your launch task
Set preLaunchTask to the build task label you created earlier
Set program to the output filename you set in the build task
Finally, whenever you want to run your app, just open the Debug/Run panel and select your launch task from the dropdown (find the name you set in launch.json). Set your breakpoints then click the Play button.
You'll get the debugger controls for stepping through your code, the variables and call stack information, and the console output in the Debug Console.

Answer 2

Maybe you should try to compile using the the flag -g
Something like
g++ -g file.cpp
This command should generate an excutable and a directory that contains information that the debugger can read.
I am no sure if this is appropiate for VS debugger since I use gdb (gnu debugger) but maybe will work