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

However, a different keyword, signed may be applied to it in order to allow negative values to be stored, but the greatest absolute value it can hold will be cut in half.

   signed char smallInteger = 238; //Wrong
   signed char smallInteger = 72;  //Ok!
   signed char smallInteger = -96; //Ok!

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.