原始字符串：ni hao, wo jiao Wang Xiao-ming.
执行ucfirst()之后：Ni hao, wo jiao Wang Xiao-ming.
执行ucwords()之后：Ni Hao, Wo Jiao Wang Xiao-ming.
执行strtoupper()之后：NI HAO, WO JIAO WANG XIAO-MING.
执行strtolower()之后：ni hao, wo jiao wang xiao-ming.
字符串中一共有：6个单词。