(C++) union

Keyword enabling you to create a union. A union is a bit like a struct, except that its variables are not seperated in memory.

Avoid union.

include <iostream>


union MyUnion
{
  unsigned int myUnsignedInt;
  int myInt;
};
int main()
{
  MyUnion myUnion;
  myUnion.myUnsignedInt = 3000000000; //Higher then the range of an int
  std::cout << myUnion.myUnsignedInt << std::endl;
  std::cout << myUnion.myInt << std::endl;
  myUnion.myInt = -69; //Below the range of en unsigned int
  std::cout << myUnion.myUnsignedInt << std::endl;
  std::cout << myUnion.myInt << std::endl;
}

This can come in handy, for converting doubles to bits:

STL example: Converting a double to a std::string of bits
C++ Builder example: Converting a double to a String of bits

Reference

1) Bjarne Stroustrup. The C++ Programming Language (3rd edition).ISBN: 0-201-88954-4 Chapter C.14.12 'Avoid union'.

last edited (November 18, 2006) by bilderbikkel, Number of views: 2500, Current Rev: 6 (Diff)

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