
string_code(+String, +Index, -Code)

   Succeeds if Code is the value of the Index'th byte in String

Arguments
   String              String
   Index               Integer between 1 and the length of String
   Code                Variable or Integer

Type
   Strings and Atoms

Description
	This predicate extracts the Index'th byte from the given string String. 
	Bytes in the string are numbered from 1 (analogous to array indices in
	subscript/3 and arg/3).


Modes and Determinism
   string_code(+, +, -) is det

Exceptions
     5 --- Index is not an integer
     5 --- String is not a string
     5 --- Code is instantiated but not to an integer
     6 --- Index is an integer less than 1 or greater than String's length
     4 --- Either Index or String are uninstantated

Examples
   
   string_code("abc", 1, 97).		% succeeds
   string_code("abc", 3, C).		% gives C = 99

   string_code("abc", 2, 100).		% fails

   string_code("abc", _, C).		% Error 4
   string_code(_, 1, C).		% Error 4
   string_code("abc", 1.5, C).		% Error 5
   string_code(abc, 1, C).		% Error 5
   string_code("abc", 0, C).		% Error 6
   string_code("abc", 4, C).		% Error 6


See Also
   string_list / 2, char_code / 2
