C some random lab for Irene :D

#include <stdio.h>
#include <math.h>
#include <string.h>

void AlgoritmulSundaram(bool marked[], int);
int Roteste(int);
int calculeazaDimensiunea(int);

void circularPrime(int n)
{
    int nNew = (n - 2) / 2;

    bool marked[nNew + 1];

    memset(marked, false, sizeof(marked));

    AlgoritmulSundaram(marked, nNew);

    printf("2 ");

    for (int i = 1; i <= nNew; i++)
    {
        if (marked[i] == true)
            continue;

        int num = 2 * i + 1;
        num = Roteste(num);

        while (num != 2 * i + 1)
        {
            if (num % 2 == 0)
                break;

            if (marked[(num - 1) / 2] == false)
                num = Roteste(num);
            else
                break;
        }

        if (num == (2 * i + 1))
            printf("%d ", num);
    }
}

// Algoritmul lui Sieve of Sundaram
void AlgoritmulSundaram(bool marked[], int nNew)
{
    // este prim daca indeplineste conditi i + j + 2ij aunde ere 1 <= i <= j
    for (int i = 1; i <= nNew; i++)
        for (int j = i; (i + j + 2 * i * j) <= nNew; j++)
            marked[i + j + 2 * i * j] = true;
}

int Roteste(int n)
{
    int rem = n % 10;
    rem *= pow(10, calculeazaDimensiunea(n));

    n /= 10;
    n += rem;
    return n;
}

int calculeazaDimensiunea(int n)
{
    int digit = 0;
    while (n /= 10)
        digit++;
    return digit;
}

int main(void)
{
    int n = 0;
    printf("Introdu n\n");
    scanf("%d", &n);
    circularPrime(n);

    // In codeblocks comenteaza getchar()
    getchar();
    getchar();
    // <--*********************-->

    return 0;
}