奇技淫巧之節省輸入輸出時間

int Scan()
{
    int res = 0, flag = 0;
    char ch;
    if((ch = getchar()) == '-') flag = 1;
    else if(ch >= '0' && ch <= '9') res = ch - '0';
    while((ch = getchar()) >= '0' && ch <= '9')
        res = res * 10 + (ch - '0');
    return flag ? -res : res;
}

void Out(int a)
{
    if(a < 0)
    {
        putchar('-');
        a = -a;
    }
    if(a >= 10) Out(a / 10);
    putchar(a % 10 + '0');
}//FROM YSF