在linux上惯用g++编译cpp. 照理说macOS只要装了g++, vscode装了C/C++的扩展包:

此外配置了下列文件就可以用g++编译:
tasks.json (compiler build settings)
launch.json (debugger settings)
c_cpp_properties.json (compiler path and IntelliSense settings)

下列是用于g++对以上3个配置文件的一份参考(出处不详):

{//tasks.json"tasks": [{"type": "cppbuild","label": "C/C++: g++ build active file","command": "/usr/bin/g++","args": ["-fdiagnostics-color=always","-g","${file}","-o","${fileDirname}/${fileBasenameNoExtension}","-std=c++17","-stdlib=libc++",],"options": {"cwd": "${fileDirname}"},"problemMatcher": ["$gcc"],"group": {"kind": "build","isDefault": true},"detail": "compiler: /usr/bin/g++"}],"version": "2.0.0"
}    

{//c_cpp_properties.json"configurations": [{"name": "Mac","includePath": ["${workspaceFolder}/**"],"defines": [],"macFrameworkPath": ["/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/System/Library/Frameworks"],"compilerPath": "/usr/bin/g++","cStandard": "c17","cppStandard": "c++17","intelliSenseMode": "gcc-x64"}],"version": 4
}  

{//launch.json"configurations": [{"name": "C/C++: debug","type": "lldb","request": "launch","program": "${fileDirname}/${fileBasenameNoExtension}","args": [],"cwd": "${workspaceFolder}","preLaunchTask": "C/C++: g++ build active file"}],"version": "2.0.0"
}

但最新macos vscode(如1.88.1)对于g++的支持似乎不那么友好, 每次试图compile或读取配置会报: Cannot find g++ build and debug active file.
很可能因为launch.json的预制配置并没有"g++ build and debug active file", 直接run的话大概率会无法编译. 

参看vscode官方doc, 他还是推荐使用clang在macos编译c++: Configure VS Code for Clang/LLVM on macOS.
于是乎我们还是抽出其中的要点, 主要还是三个配置文件:

{//tasks.json"tasks": [{"type": "cppbuild","label": "C/C++: clang++ build active file","command": "/usr/bin/clang++","args": ["-fcolor-diagnostics","-fansi-escape-codes","-g","${file}","-o","${fileDirname}/${fileBasenameNoExtension}","--std=c++17",],"options": {"cwd": "${fileDirname}"},"problemMatcher": ["$gcc"],"group": {"kind": "build","isDefault": true},"detail": "Task generated by Debugger."}],"version": "2.0.0"
}

{//c_cpp_properties.json"configurations": [{"name": "Mac","includePath": ["${workspaceFolder}/**"],"defines": [],"macFrameworkPath": ["/Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/System/Library/Frameworks"],"compilerPath": "/usr/bin/clang++","cStandard": "c11","cppStandard": "c++17","intelliSenseMode": "macos-clang-arm64"}],"version": 4
}

{//launch.json"configurations": [{"name": "C/C++: clang++ build and debug active file","type": "cppdbg","request": "launch","program": "${fileDirname}/${fileBasenameNoExtension}","args": [],"stopAtEntry": false,"cwd": "${fileDirname}","environment": [],"externalConsole": false,"MIMode": "lldb","preLaunchTask": "C/C++: clang++ build active file"}],"version": "2.0.0"
}

然后在当前c++ file点击右上角的Debug C/C++ File就可以Run了.