【模板】fread读入优化 & fwrite输出优化

#include <iostream>
#include <cstdio>
#include <cctype>

#define SIZE (1 << 21) 

#define Getchar() (pr1 == pr2 && (pr2 = (pr1 = fr) + fread(fr, 1, SIZE, stdin), pr1 == pr2) ? EOF : *pr1++)
#define Putchar(ch) (pw < SIZE ? fw[pw++] = (ch) : (fwrite(fw, 1, SIZE, stdout), fw[(pw = 0)++] = (ch))) 

char fr[SIZE], * pr1 = fr, * pr2 = fr;
char fw[SIZE];
int pw;

int Read()
{
    int res = , sign = ;
    char ch = Getchar();
    while(!isdigit(ch))
    {
        if(ch == '-') sign = -;
        ch = Getchar();
    }
    while(isdigit(ch))
    {
        res = res *  + ch - '';
        ch = Getchar();
    }
    return res * sign;
}

void Write(int val)
{
    char a[];
    int len = ;
    if(val < )
    {
        val = -val;
        Putchar('-');
    }
    do
    {
        a[++len] = val %  + '';
        val /= ;
    }
    while(val);
    while(len)
    {
        Putchar(a[len--]);
    }
    return;
}

int main()
{
    // program...
    return ;
}