From the book:(Introduction to Programing Languages

Programing in C,C++,Scheme,Prolog,C#,and SOA, 5th edition)

(chapter 1)

11. The following syntax graph defines the identifiers of a programming language, where alpha is the set of characters "a" through "z" and "A" through Z," digit is the set of characters "0" through 9," and underscore is the character." E alpha digit underscore 11.2 Give the syntax graph that defines the identifiers always starting with a letter from the set alpha. 11. The following syntax graph defines the identifiers of a programming language, where alpha is the set of characters "a" through "z" and "A" through Z," digit is the set of characters "0" through 9," and underscore is the character." E alpha digit underscore 11.2 Give the syntax graph that defines the identifiers always starting with a letter from the set alpha