Install compiler

GCC compiler for Ubuntu

sudo apt update
sudo apt install -y build-essential   # g++, gcc, make, libc headers
g++ --version

Install gdb

sudo apt update
sudo apt install -y build-essential gdb

Install vscode extensions

• C/C++ (ms-vscode.cpptools)

• CMake Tools (ms-vscode.cmake-tools)

Run and debug simple file

1. Create a file and build symbol debug

File name: hello.cpp

#include <iostream>
int main(int argc, char** argv) {
    std::cout << "argc=" << argc << "\n";
    for (int i=0;i<argc;i++) std::cout << i << ": " << argv[i] << "\n";
    return 0; // đặt breakpoint ở đây
}

Compile the file .cpp

g++ -std=gnu++17 -O0 -g hello.cpp -o hello

1. Create debug configuration (launch.json)

VS Code → Run and Debug (Ctrl+Shift+D) → “create a launch.json” → Select C++ (GDB/LLDB).

Sample configuration:

{
"version": "0.2.0",
"configurations": [
    {
    "name": "Debug hello (gdb)",
    "type": "cppdbg",
    "request": "launch",
    "program": "${workspaceFolder}/hello",
    "args": ["arg1", "arg2"],           // tham số dòng lệnh
    "stopAtEntry": false,
    "cwd": "${workspaceFolder}",
    "environment": [],
    "externalConsole": false,
    "MIMode": "gdb",
    "miDebuggerPath": "/usr/bin/gdb",
    "setupCommands": [
        { "text": "-enable-pretty-printing" }  // in đẹp std::vector, string...
    ]
    }
]
}

Run: set breakpoint and press F5

Project using CMake

1. Create CMakeLists file

File name: CMakeLists.txt

cmake_minimum_required(VERSION 3.16)
project(demo LANGUAGES CXX)

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_STANDARD_REQUIRED ON)
set(CMAKE_CXX_EXTENSIONS OFF)

set(CMAKE_BUILD_TYPE Debug)                # -g, -O0
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)      # VS Code IntelliSense

add_executable(demo main.cpp)

target_compile_options(demo PRIVATE -Wall -Wextra -Wpedantic)

Then invoke commands:

mkdir build && cd build
cmake ..
cmake --build .

1. Debug in vscode

• Select CMake Tools status bar → Select kit → GCC. (Select GCC of linux when using Ubuntu)

• Select preset Debug → Build.

• Create launch.json file then you don’t need to care about debugging script.

File name: .vscode/launch.json

{
"version": "0.2.0",
"configurations": [
    {
    "name": "CMake: Debug current target",
    "type": "cppdbg",
    "request": "launch",
    "program": "${command:cmake.launchTargetPath}",
    "cwd": "${workspaceFolder}",
    "MIMode": "gdb",
    "miDebuggerPath": "/usr/bin/gdb",
    "stopAtEntry": false,
    "setupCommands": [{ "text": "-enable-pretty-printing" }]
    }
]
}

• Invoke command Ctrl + Shift + D to open debug tab and select Cmake: Debug current target