FZ-Homework

#include <iostream>
#include <iomanip>
#include <cmath>
#include <fstream>
#include <string>
#include <cstdlib>
#include <vector>

std::string const file_name_i("./input.txt");
std::string const file_name_o("./output.txt");

std::vector<int> read_data(std::string const file_name);
void analysis(std::vector<int> collect,
              std::string const file_name,
              bool serialize = false);

int main() {
  std::vector<int> collect;

  collect = read_data(file_name_i);

  //  analysis
  analysis(collect, file_name_o, true);

  return 0;
}

// FZ

std::vector<int> read_data(std::string const file_name) {
  std::vector<int> collect;
  std::ifstream inStream;

  inStream.open(file_name);
  if (!inStream.is_open()) {
    std::string emsg("File open error: ");
    emsg += file_name;
    throw std::runtime_error(emsg);
  }

  while (!inStream.eof()) {
    int x_;
    //  just read the file and save data into a vector
    //  allows analysis of the data independent of I/O
    inStream >> x_;
    collect.push_back(x_);
  }

  //  resource cleanup
  inStream.close();

  return collect;
}

void analysis(std::vector<int> collect,
              std::string const file_name,
              bool serialize) {
  std::ofstream outStream;
  std::streambuf * coutbuf;

  if (serialize) {
    outStream.open(file_name);
    if (!outStream.is_open()) {
      std::string emsg("File open error: ");
      emsg += file_name;
      throw std::runtime_error(emsg);
    }
    coutbuf = std::cout.rdbuf();
    std::cout.rdbuf(outStream.rdbuf());
  }

  std::cout << "=== === ============" << std::endl;
  std::cout << " x  x^2 Current Sum." << std::endl;
  std::cout << "=== === ============" << std::endl;

  int sum = 0;
  for (auto xx : collect) {
    sum += xx;
    double pwr = pow(xx, 2);
    std::cout << std::setw(2)
              << xx
              << std::setw(5)
              << pwr
              << std::setw(8)
              << sum
              << std::endl; // isspace(int, pow)
  }

  double avg = (static_cast<double>(sum) / collect.size());
  std::cout << '\n'
            << "The average of these "
            << collect.size()
            << " numbers is: "
            << avg
            << std::endl;

  if (serialize) {
    //  resource cleanup
    std::cout.rdbuf(coutbuf);
    outStream.close();
  }
}