//--------------------------------------------
// NAME: Antonio Milev
// CLASS: XIb
// NUMBER: 02
// PROBLEM: #1
// FILE NAME: primes.cc
// FILE PURPOSE:
// Calculates how many prime numbers are there between
// 1 and n using multythreading.
//---------------------------------------------
#include <stdio.h>
#include <pthread.h>
#include <string.h>
#include <stdlib.h>

void *calc_prime(void *nd);

#define NUM_THREADS 1000

int main() {
	char input[200];
	pthread_t threads[NUM_THREADS];
	int tr_index = 0;
	while(1) {
		scanf("%s",input);
 		if(strcmp(input, "e") == 0) {
 			for(int t = 0;t < tr_index;t++) {
 				pthread_join(threads[t], NULL);
 			}
			break;
		} else if(strcmp(input, "p") == 0) {
			int n;
			scanf("%d",&n);
			int rc = pthread_create(&threads[tr_index], NULL, calc_prime, (void*)n);
			tr_index++;
		} else {
			printf("Supported commands:\np N - Starts a new calculation for the number of primes from 1 to N\ne - Waits for all calculations to finish and exits\n");
		}
	}
}

//--------------------------------------------
// FUNCTION: calc_prime
// Calculates how many prime numbers are there between 1 and num
// PARAMETERS:
// num - the number to which we calculate
//----------------------------------------------
void *calc_prime(void *num) {
	int n = (int)num;
	printf("Prime calculation started for N=%d\n",n);
	int prime_counter = 0;
	int is_prime = 1;
	for(int i = 2;i < n;i++) {
		for(int j = 2;j < i;j++) {
			is_prime = 1;
			if(i % j == 0) {
				is_prime = 0;
				break;
			}
		}
		if(is_prime) {
			prime_counter++;
		}
	}
	printf("Number of primes for N=%d is %d\n",n,prime_counter);
	pthread_exit(NULL);
}