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

int IsPrime(int val);
int ListOfPrime(int *tab, int *pn, int cap, int val);
void printab(const int* tab, int nb);
int CheckCreditCardNumber(const char * s);


int main (void){
    /*int tab[15];
    int nb;
    printf("retval: %d\n", ListOfPrime(tab, &nb, 7, 15));
    printab(tab, nb);*/
    int cap=64;
    char CreditCardNumber[cap];
    strncpy(CreditCardNumber,"4975386536611119",cap);
    CreditCardNumber[cap-1]='\0';
        int validcard=CheckCreditCardNumber("4975386503611416");
        if(validcard==0)
        {

        printf("%s is a valid credit card number \n", CreditCardNumber);
        }
        else

        {
           printf("%s is not a valid credit card number \n", CreditCardNumber);
        }
}

void printab(const int* tab, int nb){
    int i;
    printf("[");
    for (i=0; i< nb; i++){
        printf("%d", tab[i]);
        if (i<nb-1){
            printf(", ");
        }
    }
    printf("]\n");
}

int ListOfPrime(int *tab, int *pn, int cap, int val){ // 5 + 1 pour la ligne du main
    int i;

    if(val < 2) return 2; // 1 point

    *pn = 0; // 0.5 point
    for(i=1; i<=val; i++){  // 1point
        if(IsPrime(i) == 1){ //1 point
            if(*pn < cap){
                tab[*pn] = i; // 0,5 point
                (*pn)++; // 0,5 point
            }
            else{
                return 1; // 0.5 point
            }
        }
    }

    return 0;
}

int IsPrime(int val){ //4 points
    int i;
    int bound;

    if(val == 0) return 0;
    bound = val/2;
    for(i=2; i<bound; i++){ //
        if(val % i == 0){
            return 0;
        }
    }
    return 1;
}


int CheckCreditCardNumber(const char * s){ //10 points
    int i=0;
    int len;
    int cap=64;
    int card[cap];
    int sum;

    i = 0;
    while(s[i] != '\0'){   // 1 point
        if (i+1 >=cap) return 2; // 1 point
        if (s[i] < '0' || s[i] > '9'){ // 1 point
            return 1;
        }
        else{
            card[i] = s[i] - '0'; // 1 point
        }
        i++;

    }
    len=i;
    printab(card, len);

    for(i=len-2 ; i>=0 ; i=i-2){ // 1 point
        card[i] = (card[i]*2); // 1 point
        if(card[i]>9) card[i]=card[i]-9;
    }

    printab(card, len);

    sum = 0;
    for(i=0 ; i<len ; i++){ // 1 point
        sum += card[i];  // 1 poijnt
    }


    if(sum%10 == 0) return 0; // 1 point

    return 3; // 1 point
}