mac端VScode运行C++11报错，配置VScode，使其支持C++11及以后的标准

新装的VScode在运行C++11程序时，可能报错，例如这个程序：

#include<iostream>
#include<string>
#include<vector>
using namespace std;

int main(){
    int b = 1;
    auto a = b;
    cout << a << endl;
    vector<string> msg{"Hello", "C++", "World", "from", "VS Code", "and the C++ extension!"};
    int len = msg.size();
    cout << "长度" << len << endl;
    for (int i=0; i<5; i++){
        // ms.push_back("a");
        cout << i << endl;
    }

    return 0;
}

此程序会报错以下错误：

expected';' at end of declaration gcc [Ln 10, Col 23] 
'auto' type specifier is a C++11 extension [-Wc++11-extensions] gcc [Ln 8, Col 5]

此时，修改下tasks.json即可，打开tasks.json，将内容修改为：

{
    "tasks": [
        {
            "type": "cppbuild",
            "label": "C/C++: g++ 生成活动文件",
            "command": "/usr/bin/g++",
            "args": [
                "-std=c++17",
                "-stdlib=libc++",
                "-fdiagnostics-color=always",
                "-g",
                "-Wall",
                "${file}",
                "-o",
                "${fileDirname}/${fileBasenameNoExtension}"
            ],
            "options": {
                "cwd": "${fileDirname}"
            },
            "problemMatcher": [
                "$gcc"
            ],
            "group": {
                "kind": "build",
                "isDefault": true
            },
            "detail": "调试器生成的任务。"
        }
    ],
    "version": "2.0.0"
}

此时运行一切正常：

如果想在终端输出结果，进行debug即可：