den 4

include <stdio.h>
#include <stdlib.h>

void setBit(int* mask, int n)
{
    *mask |= (1 << n);
}

void eraseBit(int* mask, int n)
{
    *mask &= ~(1 << n);
}

int isSet(int mask, int n)
{
    return mask & (1 << n);
}

int onesCount(int mask)
{
    int count = 0;
    for (int i = 0; i < sizeof(int) * 8; i++)
    {
        if (isSet(mask, i))
            {
            count++;
        }
    }
    return count;
}

int zerosCount(int mask)
{
    return sizeof(int) * 8 - onesCount(mask);
}

void IsHere(int mask)
{
    for(int i =0; i < sizeof(int) * 8; i++)
        {
        if(isSet(mask, i))
        {
            printf("\nUchenik %d prisustva\n", i);
        }
    else
        {
            printf("\nUchenik %d otsustva\n", i);
        }
    }
}

int IsNotHere(int mask, int n)
{
    return isSet(mask, n) ? 0 : 1;
}

int Validation(int n)
{
    return n > 32 || n < 0 ? 0 : 1;
}
int main()
{

    int prisustviq = 0;
    int option;

    while (1)
        {
        printf("1. Napishi prisustvie\n");
        printf("2. Napishi otsustvie\n");
        printf("3. Information\n");
        printf("4. Proveri prisustvashti/otsustvashti po nomer\n");
        printf("5. Exit\n");

        printf("Enter option: ");
        scanf("%d", &option);


        if (option == 1)
        {
            int n;
            printf("Nomer na uchenika: ");
            scanf("%d", &n);

            if(Validation(n))
                {
                setBit(&prisustviq, n);
            }
            else
                {
               printf("Invalid number\n");
            }
        }
        else if (option == 2)
            {
            int n;
            printf("Nomer na uchenik: ");
            scanf("%d", &n);

            if(Validation(n))
                {
                eraseBit(&prisustviq, n);
            }
            else
                {
               printf("Invalid number\n");
            }
        }
        else if (option == 3)
            {
            printf("Broi prisustvashti: %d\n", onesCount(prisustviq));
            printf("Broi otsustvashti: %d\n", zerosCount(prisustviq));
            IsHere(prisustviq);
        }
        else if (option == 4)
        {
            int n;
            printf("Nomer na uchenika: ");
            scanf("%d", &n);

            if(Validation(n))
                {
               if(IsNotHere(prisustviq, n))
               {
                    printf("Uchenik %d prisustva\n", n);
                }
            else
                {
                    printf("Uchenik %d otsustva\n", n);
                }
            }
            else
                {
                printf("Invalid number\n");
            }
       }
       else if(option == 5)
        {
            break;
       }
       else
        {
            printf("Invalid command \n");
        }
    }
    return 0;
}