Question

Write a multi-threaded program that outputs prime numbers. The program should work as follows: the user will run the program and enter a number on the command line. The program creates a thread that outputs all the prime numbers less than or equal to the number entered by the user. Also, create a separate thread that outputs this subset of the above primes that have the following property: the number that is derived by reversing the digits is also prime (e.g., 79 and 97).

Answer 1

Answer:

The programming code can be found in the explanation part, please go through it.

Explanation:

Code:

#include<stdio.h>

#include<stdlib.h>

#include <pthread.h>

// function check whether a number

// is prime or not

int isPrime(int n)

{

// Corner case

if (n <= 1)

return 0;

// Check from 2 to n-1

for (int i = 2; i < n; i++)

if (n % i == 0)

return 0;

return 1;

}

void* printPrimes(void *vargp)

{

int *n = (int *)vargp;

int i=0;

for (i=2;i<=n;i++)

{

if (isPrime(i)) printf("%d\n", i);

}

}

// Driver Program

int main(int argc, char* argv[])

{

int n = atoi(argv[1]);

pthread_t tid;

pthread_create(&tid, NULL, printPrimes, (void *)n);

pthread_exit(NULL);

return 0;

}