Untitled

#include <stdio.h>


int isValidNum(int n)
{
    if(n < 1000 || n > 9999) return 0;
    
    int seen[10] = {0};
    for(int i = 0; i < 4; i++)
    {
        int digit = n % 10;
        
        if(seen[digit] != 0) return 0;
        seen[digit]++;
        
        n /= 10;
    }
    
    return 1;
    
}

int is_shot(int num, int guess) // the function returns how many digits are in the same place
{
    if(num == 0  || guess == 0) return 0;
    return (num%10 == guess%10) + is_shot(num/10, guess/10);
}


int is_hit_helper(int num, int n) // helper function for is_hit()
{
    if(num == 0) return 0;
    return (num%10 == n) + is_hit_helper(num/10, n);
}

int is_hit(int num, int guess) // the function returns how many simillar digits there are
{
    int count = 0;
    while(guess != 0)
    {
        count += is_hit_helper(num, guess%10);
        guess /= 10;
    }
    return count;
}


int get_num(int turn) // the function returns a valid num from the user
{
    int num;
    do{
        printf("Player %d, enter your number: ", turn);
        scanf("%d", &num);
    } while(!isValidNum(num));
    
    return num;
}


int main()
{
    int p1_num, p2_num;
    int winner;
    int current_guess = 0;
    int current_turn = 0;
    int turns_counter = 0;
    
    p1_num = get_num(1);
    p2_num = get_num(2);
    
    int nums[] = {p1_num, p2_num};
    
    
    printf("----- TIME FOR GUESSES -----\n");
    
    
    while((current_turn == 1 && current_guess != p2_num) ||
       (current_turn == 0 && current_guess != p1_num))
    {
        current_guess = get_num(current_turn+1);
        
        printf("Player %d has %d hits and %d shots.\n", current_turn + 1, 
                is_hit(nums[!current_turn], current_guess), 
                is_shot(nums[!current_turn], current_guess));
        
        current_turn = !current_turn;
        turns_counter++;
    }

    if(current_guess == p1_num) winner = 2;
    else winner = 1;
    
    printf("The GREAT winner is Player %d. Guessed the number by %d turns. ", winner, 
        turns_counter/2 + current_turn);
    
    return 0;
}