关于VS code的编译链接，以及CMake、CMake Tools的使用

Shortcut keys:
    build program  ---->   ctrl+shift+B
    run program ----->  F5

    for example with command line:
        build_link -----> g++ example.cpp -o 1 `pkg-config opencv --cflags --libs opencv`
        run script  ------> ./1

use cmake
    1.write CMakelists.txt,add executable
    2.Command line input:
    $ mkdir build_xxx
    $ cd build_xxx
    $ cmake ..
    $ make

gcc complier and link:
    gcc -pthread -o outfile.out haircut.cpp

Custom Compilation(Reference link:https://blog.csdn.net/u010677365/article/details/80703984)
    use cmake tools with VS Code(required cmake minimum version 3.7.0)
    ctrl+shift+P  ----> input:  Tasks:Configure Task -----
    ---> select first options  -----> goto tasks.json
    ----> configure "args" -----> add library files


Compiling with plug-ins(recommended)
    1.install CMake, CMake Tools
    2.ctrl+shift+P input :cmake quick start
    3.enter the project name and select the type of CMakeList(executable file)
    4.F7 or shift+F7  to automatic generate build file and place the build target
    under the build folder
    5.run the build directory directly as an executable file