How do I cancel threads and lock and still have the code work?

Question

I'm trying to fix this code instead of using threads and locks i am using parent and child process with fork() method. But only the producer method is producing and the consumer isn't consuming anything. I looked it up and found that they are not sharing the same memory space. As if they are two separate buffers. I want to make the use the same buffer. Can anyone help me with this? i am using terminal Linux

#include <iostream>
#include <queue>
#include <condition_variable>
#include <unistd.h>
#include <chrono>
using namespace std ;

std::queue<int> buffer;

std::condition_variable cv;
int emptybuffer=5; //checks if there is any empty slots
int fullbuffer=0; // checks if there is any full slots

void producer()
{ int i=1;
   while(emptybuffer>0)
   {



        buffer.push(i);
        std::cout << "Produced: " << i << std::endl;
        i++;
        
       
            emptybuffer--;
             fullbuffer++;

            }

            usleep(1000 * 1000);  // 500 milliseconds

}
void consumer() {
while (fullbuffer>0)  
  {
        int data = buffer.front();
        buffer.pop();
        std::cout << "Consumed: " << data << std::endl;
      emptybuffer++;
fullbuffer--;

        
    }

// Sleep to simulate some work being done
        usleep(1000 * 1000); // 1000 milliseconds
    
}



    
int main() 
{ 
    pid_t c_pid = fork(); 
  
    if (c_pid == -1) { 
        perror("fork"); 
        exit(EXIT_FAILURE); 
    } 
    else if (c_pid > 0) { 
        //  wait(nullptr);
        producer(); 
        cout << "printed from parent process " << getpid() 
             << endl; 
   exit(0);
    } 
    else {
consumer();
 
        cout << "printed from child process " << getpid() 
             << endl;
exit(0); 
    } 
  
    return 0; 
}