c++【IO挂】【输入输出挂】

输入挂

int read()   //代替scanf，速度更快，俗称输入挂
{
    char ch=' ';
    int ans=0;
    while(ch<'0' || ch>'9')
        ch=getchar();
    while(ch<='9' && ch>='0')
    {
        ans=ans*10+ch-'0';
        ch=getchar();
    }
    return ans;
}

 int n = read();

输出挂

void out(int a)  //代替printf，速度更快，俗称输出挂
{
    if(a > 9)
    {
        out(a/10);
    }
    putchar(a%10 + '0');
}
out(n);