#include<stdio.h>
#include<omp.h>
main()
{
    int prime[1000],i,j,n;
    printf("\nIn order to find prime numbers from 1 to n, enter the value of n:");
    scanf("%d",&n);
    for(i=1;i<=n;i++)
    {
        prime[i]=1;
    }
    prime[1]=0;
    for(i=2;i*i<=n;i++)
    {
/* multi-threading to remove multiples of prime number i
from the list (array) */
    #pragma omp parallel for
    for(j=i*i;j<=n;j=j+i)
    {
        if(prime[j]==1)
        prime[j]=0;
    }
}
    printf("\nPrime numbers from 1 to %d are\n",n);
    for(i=2;i<=n;i++)
    {
        if(prime[i] == 1)
        {
            printf("%d\t ",i);
        }
    }
printf("\n");
}

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