Working with C++ vectors.

cpsc120_vector.cc

// Gist https://gist.github.com/mshafae/ff7818bd3514ad0539e90b5d2f8933b3
// Filename cpsc120_vector.cc
// CompileCommand clang++ -std=c++17 cpsc120_vector.cc
// Working with C++ vectors.

#include <iostream>
#include <vector>

int main(int argc, char const* argv[]) {
  std::vector<int> even_numbers{2, 4, 6, 8, 10};

  for (int index = 0; index < even_numbers.size(); index++) {
    std::cout << "The even number at " << index << " is "
              << even_numbers.at(index) << ".\n";
  }

  std::vector<int> odd_numbers;
  // Example of a for loop with two different counters
  for (int index = 0, counter = 1; index < even_numbers.size();
       index++, counter += 2) {
         // Add numbers to the back of the vector.
    odd_numbers.push_back(counter);
  }

  int index{0};
  for (int number : odd_numbers) {
    std::cout << "The odd number at " << index << " is " << number << ".\n";
    index = index + 1;
  }

  // We can catch the error and handle it gracefully.
  try {
    std::cout << "The even number at " << 123456 << " is "
              << even_numbers.at(123456) << ".\n";
  } catch (std::exception const& e) {
    std::cout
        << "We tried to find something outside the bounds of our array and we "
           "nearly crashed.\n";
    std::cout << e.what() << "\n";
  }
  // flush everything out to stdout.
  std::cout << std::flush;
  // This will probably NOT cause the program to fail but it doesn't make sense.
  std::cout << "The even number at " << 123456 << " is " << even_numbers[123456]
            << ".\n";

  // flush everything out to stdout.
  std::cout << std::flush;
  // This will cause the program to fail.
  std::cout << "The even number at " << 123456 << " is "
            << even_numbers.at(123456) << ".\n";
  return 0;
}