Code builds and runs, but shows red squiggles. using CMAKE in vs code, C++

Question

i have just started to use vscode and CMAKE. and to learn this i have made a simple project in this regard

My code builds and runs, however the red squiggles does not seem to go away. what should i do, is it still a stable program??

project structure:

|CMakeLists.txt

|App

+---CMakeLists.txt

+---main.cpp

|Source_DIR

+---CMakeLists.txt

+---src

------+---helloworld.cpp

+---include

------+---helloworld.h

toplevel cmakelists.txt:

cmake_minimum_required(VERSION 3.15...3.18)

project(Project_RetroTron VERSION 1.0.0) 

add_subdirectory(source_DIR)                                                                                                                                                                                                                                           
add_subdirectory(app)

source_DIR/cmakelists.txt:

add_library(hello_world 
src/helloworld.cpp)

target_include_directories(hello_world PUBLIC PUBLIC 
$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>)

source_DIR/include/helloworld.h

#ifndef HELLOWORLD_H
#define HELLOWORLD_H

class helloWorld
{
public:
    helloWorld();    
};

#endif

source_DIR/src/helloworld.cpp

#include <iostream>
#include "helloworld.h"



helloWorld::helloWorld()
{
std::cout <<"hello my man" << std::endl;
}

app/CMakeLists.txt

add_executable(helloworldMain main.cpp)


target_link_libraries(helloworldMain PRIVATE hello_world)

app/main.cpp

#include <iostream>
#include <stdio.h>
#include "helloworld.h"
int main()
{
helloWorld heya;   
}

i also use cmake-tools which generates this .vscode folder with a settings.JSON file on the top level of the hiearchy:

{
"C_Cpp.default.configurationProvider": "ms-vscode.cmake-tools"
}

used vscode on windows. the build have been erased and rerun so it does not have any old files to refer to.

why do i still have an error!!!

this is the result of a build and run, adn as you can see it runs fine:

cmake make generation

build

run

still it shows error