Undefined reference to winmain when trying to compile class implementation

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C++

I'm a beginner in C++ and learning OOP. I wrote the main file, a header and a class implementation file

Main file (main.cpp):-

#include 
#include "cylinder.h"

int main(){
    
    Cylinder cylinder1(10,10);
    std::cout << cylinder1.volume() << std::endl;

    return 0;
}

Header file (cylinder.h):-

#ifndef cylinder_h
#define cylinder_h

class Cylinder{
	private:
		double radius;
		double height;

	public:
		Cylinder() = default;
		Cylinder(double r, double h);
		double volume();
};

#endif

Class implementation file (cylinder.cpp):-

#include "cylinder.h"

Cylinder::Cylinder(double r, double h){
	radius = r;
	height = h;
}
double Cylinder::volume(){
	return 3.14*radius*radius*height;
}

When I run the class implementation file I get error

Quote:

undefined reference to `WinMain'
collect2.exe: error: ld returned 1 exit status

What I have tried:

I have tried it on VS Code and if the entire class is in the header file the program works just fine. The problem arises when the I split the class into header file and the cpp implementation file.