[[PC:~/WorkSpace/CPP/string/3.2.3$ ./constructors.exe
str1: 这是一个空串!
str1: This is a string
str2: HHHHH
str3: This is a string
str4: s is a string
str5: is a str
lexy@LexyPC:~/WorkSpace/CPP/string/3.2.3$ #include <iostream>
lexy@LexyPC:~/WorkSpace/CPP/string/3.2.3$ #include <string>
lexy@LexyPC:~/WorkSpace/CPP/string/3.2.3$
lexy@LexyPC:~/WorkSpace/CPP/string/3.2.3$ using std::cout;
using std::endl;
using std::string;