题解 | #[NOIP2008]ISBN号码#

#include <stdio.h>
#include <math.h>
int main()
{
    char isbn[14] = {0};
    scanf("%s", isbn);
    int sum = 0;
    int j = 1;
    int i = 0;
    for(i=0; i < 12; i++)
    {
        if(isbn[i] >= '0' && isbn[i] <= '9')
        {
            sum += (isbn[i] - '0')*(j++);
        }
    }

    sum %= 11;//识别码
    char s = 0;
    if(sum != 10)
    {
        s = sum+'0';
    }
    else {
        s = 'X';
    }

    if (isbn[i] == s)
    {
        printf("Right\n");
    }
    else {
        isbn[i] = s;
        printf("%s\n", isbn);
    }
    return 0;
}