printf.txt

重载＋＝为字符串的连接

Convention Constuctor:happy
Convention Constuctor:birthday
Convention Constuctor:
s1 is "happy"; s2 is "birthday"; s3 is empty 
The results of comparing s2 and s1:
s2==s1 yields0
s2!=s1 yields1
 s2>s1 yields0
s 2<s1 yields1
s2>=s1 yields0
s2<=s1 yields1

Testing!s3: 
s3 is empty; assigning s1 to s3; 
operator=called
s3 is "happy"

s1+=s2 yieldss1=happybirthday

s1+="to you"yields
Convention Constuctor:to you
Destructor:to you
s1=happybirthdayto you

Convention Constuctor: