Dumb pager program

page.cpp

#include <sys/ioctl.h>
#include <unistd.h>
#include <termios.h>

#include <iostream>
#include <fstream>
#include <string>
#include <cstdio>

int main(int argc, char* argv[])
{
    int ret = 0;

    struct termios t, save;
    tcgetattr(STDIN_FILENO, &t);
    save = t;
    t.c_lflag &= ~(ICANON | ECHO);
    tcsetattr(STDIN_FILENO, TCSAFLUSH, &t);

    struct winsize w;
    ioctl(STDOUT_FILENO, TIOCGWINSZ, &w);

    const int pagesize = w.ws_row;
    std::ifstream ifs(argv[1]);
    if (!ifs) {
        std::perror("Error");
        ret = errno;
        goto exit;
    }

    while (!ifs.eof()) {
        std::string line;
        for (int i = 1; i < pagesize and std::getline(ifs, line); i++) {
            std::cout << line << std::endl;
        }
        std::cin.get();
    }

exit:
    tcsetattr(STDIN_FILENO, TCSAFLUSH, &save);
    return ret;
}