哪个厉害的人用c求解一下

哪个厉害的人求解一下，用c语言，字符数组求解，该怎么用，怎么写，静待佳音

#include <stdio.h>

int main()
{
    char year[] = "年月日";
    char out[30] = {0}, ch;
    int cnt = 0, inx = 0;

    do
    {
        ch = getchar();
        if (ch == '.' || ch == '\n')
        {
            out[inx++] = year[cnt++];
            out[inx++] = year[cnt++];
        }
        else
            out[inx++] = ch;
    } while (ch != '\n');

    puts(out);

    return 0;
}