How to use the head file in my CPP project under WSL?

It works!
I follow your scheme, adding add_executable( test test_lance.cpp) in the end of CMakeLists.txt, then I make and run ./test, the cpp file is successfully excuted.

However, I suffer the same error when I want to run the “simple-real-numbers.cpp” example in VS Code editor.

/usr/bin/g++ -fdiagnostics-color=always -g /home/lance/code/cpp_test/test_lance.cpp -o /home/lance/code/cpp_test/test_lance
/home/lance/code/cpp_test/test_lance.cpp:38:10: fatal error: openfhe.h: No such file or directory
   38 | #include "openfhe.h"
      |          ^~~~~~~~~~~
compilation terminated.

According to official document, I add following comments in setting.json:

{
    "configurations": [
        {
            "name": "Linux",
            "includePath": [
                "${workspaceFolder}/**",
                "/usr/local/include/openfhe/core", // I added these three lines.
                "/usr/local/include/openfhe/pke",
                "/usr/local/include/openfhe/cereal"
            ],
            "defines": [],
            "compilerPath": "/usr/bin/gcc",
            "cStandard": "gnu17",
            "cppStandard": "gnu++14",
            "intelliSenseMode": "linux-gcc-x64",
            "configurationProvider": "ms-vscode.makefile-tools"
        }
    ],
    "version": 4
}

launch.json is:

takes.json is:

{
    "tasks": [
        {

            "label": "buildCmake",
            "type": "shell",
            "command": "cd build && rm CMakeCache.txt && cmake .. -DCMAKE_BUILD_TYPE=Debug && make",    
            "args": [
                "-fdiagnostics-color=always",
                "-g",
                "${file}",
                "-o",
                "${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"
}

How I fix this problem?