drop all `'\n'` except last one (just leave it in the buffer,won't get it and will finally drop it).

read until `'\n'` and replace `'\n'` with `'\0'`.

same with getline, replace `'\n'` with `'\0'`.

but …

#include <iostream>

#include <vector>

#include <string>

#include <stack>
#include <ctime>
#include <windows.h>

const int n = 1024*1024*500;

using namespace std;
class timer
{
    long long t;

  public:
    timer()
    {
        t = clock();
    }
    ~timer()
    {
        cout << clock() - t << endl;
    }
};
size_t strlen1(const char *str)
{
    register int length = 0;

    while (*str++)

        ++length;

    return (length …