Before writing a specific program, you need to run it through the command line to determine the specific function according to the input parameters. Parsing argv is very troublesome, so Google's gflags library is used. This tool can easily parse command line parameters. gflags official function introductionHow To Use gflags (formerly Google Commandline Flags)

1. Download the source code of gflags:gflags
2. The gflags-master obtained by cloning is the source code of gflags and needs to be compiled. Open CMake, fill in the source code path and compilation path as needed, and click Configure after setting:

   

    

3. Select the compiler version, if you want to use it in a 64-bit environment, select the Win64 version, and then click Finish:

   

4. If the configuration is successful, the dark interface will be displayed. Check the items that need to be generated as needed. After checking, click Generate:

   

    

5. Generated successfully, click Open Project:

   

    

6. Select the compilation environment according to your needs in VS. The default is Debug. If you need Release, choose to generate in the Release environment. Right-click on ALL_BUILD and INSTALL-generate, which may report errors, generally ignore:

    

7. After the compilation is successful, if you want to use it in the project, you also need to configure the environment variables. Right-click on the solution-configure and select the VC++ directory. The include directory is the address of the include folder in the previously compiled folder. The library directory is The address of lib\Release (or Debug) in the folder:

    

8. Select the linker-input and write gflags_static.lib, gflags_nothreads_static.lib, shlwapi.lib in the additional dependencies;
   
9. The configuration is successful. You can also refer to this article based on learning how to use it from the official documentation:The google gflags library is fully used
10. Write a program to test:

    #include <iostream>
    #include <gflags/gflags.h>
    DEFINE_string(var, "", "input var");
    int main(int argc, char ** argv) {
    	google::ParseCommandLineFlags(&argc, &argv, true);
    	std::cout << FLAGS_var << std::endl;
    	system("pause");
    	return 0;
    }
    

     

11. Right-click on the solution-Properties-Debug, enter -var test in the command parameters
12. Compile and run, check the result, if the command line parameter information is output, the setting is successful:

    

     

13. Next, you can use the gflags library to parse the command line parameters. More advanced features can be learned in the documentation.