C++ Linking error in either the header or the .cpp file associated with the header

Question

I am getting a LNK2005 error when attempting to run a build. My program compiles, but does not link, and crashes when ran. The error seems to be in either the SStack.h or the SStack.cpp file. I do not know why there is a linking error.

The exact error is

LNK2005 "public: bool __thiscall SStack::IsEmpty(void)const " (?IsEmpty@SStack@@QBE_NXZ) already defined in Main.obj    Project02_SchaferSam    C:\Users\Sam\source\repos\Project02_SchaferSam\SStack.obj   1

This is the same for every one of my constructors and member functions, they all have the same error. I have deleted the SStack.obj file and tried a clean make, but the error still persists.

The SStack.h code:

//CONTENTS: Declares Class SStack, with data members, constructors and member function prototypes
//If you want, you can make minor changes to this header file

#ifndef _StackClass_
#define  _StackClass_



#include <cstdlib>
#include <string>
#include <iostream>


using namespace std;

class SStack
{

        
        public:
                // Constructor
                SStack( int cap);
                // Copy Constructor
                SStack( const SStack& s );
                ~SStack( ); //destructor
                
        // The member function push: Precondition:  the stack is not full.
                void push ( const std::string s);
                
        // The member function pop: Precondition:  the stack is not empty.
                void pop ();

        // The member function top: Precondition:  the stack is not empty.
                string top () const;
                
                bool IsEmpty () const;

        //printing all the elements in the stack
        void print() const;

        int size() const;

        int getCapacity() const;
        

        private:
                int capacity; // Capacity is the maximum number of items that a stack can hold
                std::string* DynamicStack; 
                int used; // How many items are stored in the stack
};

#endif

The SStack.cpp code:

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

SStack::SStack(int cap)
{
    DynamicStack = new string[cap];
    this->capacity = cap;
    this->used = -1;
}

SStack::SStack(const SStack& s)
{
    capacity = s.capacity;
    DynamicStack = new string[capacity];
    used = s.used;

    for (int i = 0; i < used; i++) {
        DynamicStack[i] = s.DynamicStack[i];
    }
}

SStack::~SStack()
{

}

void SStack::push(const std::string s)
{
    if (used >= capacity - 1) {
        cout << "Stack overflow" << endl;
    }
    else {
        this->used++;
        DynamicStack[used] = s;
        cout << s << "pushed onto the stack" << endl;
    }
}

void SStack::pop()
{
    if (used < 0) {
        cout << "stack underflow" << endl;
    }
    else {
        string s = DynamicStack[used];
        this->used--;
    }
}

string SStack::top() const
{
    if (used < 0) {
        cout << "stack is empty" << endl;
        return 0;
    }
    else {
        string s = DynamicStack[used];
        return s;
    }
}

bool SStack::IsEmpty() const
{
    if (used < 0) {
        return true;
    }
    else {
        return false;
    }
}

void SStack::print() const
{
    for (int i = used; i >= 0; i--) {
        cout << DynamicStack[used] << endl;
    }
}

int SStack::size() const
{
    return used;
}

int SStack::getCapacity() const
{
    return capacity;
}

The main.cpp code is currently empty:

// Project02_SchaferSam.cpp : This file contains the 'main' function. Program execution begins and ends there.
//

#include <iostream>
#include "SStack.cpp"
#include "SStack.h"


int main()
{
    
    
}