摘要：
1. Define Storage Classes and explain application domain.register- tell to the compiler for use a CPU register for fast aceess for that variable.auto- it's a variable created and initialized when it is defined. It is not visible outside of the block.static- defined inside ofthe function retain i 阅读全文
摘要：
Given a digit string, return all possible letter combinations that the number could represent.A mapping of digit to letters (just like on the telephone buttons) is given below.Input:Digit string "23"Output: ["ad", "ae", "af", "bd", "be", &q 阅读全文