CPSC 120 Example of using trunc to truncate a double and static_cast to convert a double to an int.

cpsc120_trunc_convert_double.cc

// cpsc120_trunc_convert_double.cc
// Gist https://gist.github.com/mshafae/7b281ca822da831d8ffb85982034c917

#include <cmath>
#include <iostream>
#include <limits>

int main(int argc, char const *argv[]) {
  // This is a really large number, a 1 with 308 zeros after it.
  // double decimal_number{1.0e308};
  // This is a relatively small number.
  double decimal_number{123.456};
  double integer_part{NAN};
  int converted_and_truncated{0};
  // Is decimal_number safe to truncate and convert to an integer? Check to see
  // if it is less than the largest int and greater than the smallest int.
  if (decimal_number < std::numeric_limits<int>::max() &&
      decimal_number > std::numeric_limits<int>::min()) {
    integer_part = trunc(decimal_number);
    converted_and_truncated = static_cast<int>(integer_part);
    std::cout << "Converted " << decimal_number << " to "
              << converted_and_truncated << "\n";
  } else {
    std::cout << "Cannot convert " << decimal_number << " to an int.\n";
  }
  return 0;
}