Char

A character is, programmatically, one ASCII number value used to represent a keyboard character('a', 'x', '1', '6', 'ê'). This variable is declared by the name char, and its value must be surrounded by apostrophes:

   char anA = A;  //Wrong
   char anA = "A";  //Wrong
   char anA = 'A';  //Correct

At its core, a char is really just an 8-bit integer, its value ranging from 0 to 255. In fact, if you require a integer to store a very small value, a character can be used for this purpose, but it is important to remember that if you wish to use a char for this purpose that they are by definition unsigned:

   char smallInteger = 127;  //Ok!
   char smallInteger = -23;  //Wrong

This is why when assigning a char an ASCII number value you must use apostrophes, so that the compiler know to convert that keyboard character into its 8-bit ASCII value.

Strings are arrays of, or pointers to Characters. These are used more often than characters are in the Source Engine.