2.4.cpp

#include <iostream>

int main() {
  unsigned u = 10, u2 = 42;
  std::cout << u2 - u << std::endl;  // 32
  std::cout << u - u2 << std::endl;  // 4294967264 = -32 + 4,294,967,296

  int i = 10, i2 = 42;
  std::cout << i2 - i << std::endl;  // 32
  std::cout << i - i2 << std::endl;  // -32
  std::cout << i - u << std::endl;   // 0
  std::cout << u - i << std::endl;   // 0

  // Mix unsigned with signed.
  std::cout << i - u2 << std::endl;  // 4294967264 = -32 + 4,294,967,296
  std::cout << u2 - i << std::endl;  // 32
  std::cout << i2 - u << std::endl;  // 32
  std::cout << u - i2 << std::endl;  // 4294967264 = -32 + 4,294,967,296

  int i3 = -10;
  std::cout << i3 + u << std::endl;  // 0 = -10 + 4,294,967,296 + 10 - 4,294,967,296
  std::cout << i3 - u << std::endl;  // 4294967276 = -10 + 4,294,967,296 - 10

  return 0;
}