暮色呼如
size语法:size_type size();size()函数返回字符串中现在拥有的字符数。长度(length)语法:size_type length();length()函数返回字符串的长度. 这个数字应该和size()返回的数字相同.Actually, they have equal results, but semantics is different.size() act as a method of container, like vector ,set and so forth.length() represent a property of sequence.