42: uniq

Implement the first command line tool, uniq.

View Source file uniq.cpp Only

//https://www.gnu.org/software/coreutils/manual/html_node/uniq-invocation.html 
#include <fmt/core.h>
#include <iostream>
#include <unistd.h>
#include <fstream>
#include <vector>
#include <algorithm>

void uniq_file(std::istream& in) {
  std::string prev;
  std::string line;

  // first line is always printed to start
  getline(in, prev);
  fmt::print("{}", prev);

  while(in) {
    getline(in, line);

    if(line != prev) {
      fmt::println("{}", line);
      prev = line;
    }
  }
}


int main(int argc, char* argv[]) {
  if(argc > 1) {
    for(int i = 1; i < argc; i++) {
      std::ifstream in_file{argv[i]};
      uniq_file(in_file);
    }
  } else {
    uniq_file(std::cin);
  }
}