Extend the While language with (limited) string support.
“character. There can be any number of any characters except newlines and
”characters. Backslach is allowed inside string literals, but it has no special meaning (unlike in real programming languages).
length: takes a string and returns an integer, the number of characters in the string
concat: takes two strings and returns a string, the concatenation of the parameters
lengthfunction just returns the stored number, and