Submission

Score: 100

User: samsenpisardmoo

Problemset: ตรวจบัตรเครดิต

Language: c

Time: 0.001 second

Submitted On: 2025-09-30 00:15:35

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

int main() 
{
    char card[20];
    scanf("%s", card);

    int len = strlen(card);
    int sum = 0;

    int checkDigit = card[len - 1] - '0';

    int pos = 0;
    for (int i = len - 2; i >= 0; i--, pos++) 
    {
        int num = card[i] - '0';


        if (pos % 2 == 0) 
        {
            num *= 2;
            if (num > 9) num = (num / 10) + (num % 10);
        }
        sum += num;
    }

    int Check = (10 - (sum % 10)) % 10;

    if (Check == checkDigit) 
    {
        printf("yes");
    }
    else 
    {
        printf("no");
    }

    return 0;
}