what's the outcome? - 未名空间MITBBS历史存档

国际科技财经博客移民网络热点娱乐民生时事公众号

Redian新闻

>未名空间

>Programming - 葵花宝典

what's the outcome?

what's the outcome?# Programming - 葵花宝典

m*g2007-11-19 08:11

1 楼

string a1 = "Hello";
string a2 = "world!";
string* s1 = 0;
string& s2 = a1;
s1 = &a1;
s2 = a2;
std::cout << *s1 << " " << s2 << std::endl;
and why?

j*k2007-11-19 08:11

2 楼

//after this line s1=s2
//so outcome is world! world!
Am I right?

【在 m**g 的大作中提到】

: string a1 = "Hello";
: string a2 = "world!";
: string* s1 = 0;
: string& s2 = a1;
: s1 = &a1;
: s2 = a2;
: std::cout << *s1 << " " << s2 << std::endl;
: and why?

d*d2007-11-19 08:11

3 楼

I think you are right.

【在 j*****k 的大作中提到】

:
: //after this line s1=s2
: //so outcome is world! world!
: Am I right?

d*d2007-11-19 08:11

4 楼

s1是a1的地址，s2是a1的reference,不能说s1 = s2.

【在 j*****k 的大作中提到】

:
: //after this line s1=s2
: //so outcome is world! world!
: Am I right?

j*k2007-11-19 08:11

5 楼

那后面s2=a2了，就不是s2变成a2的reference了？
还是说s2就只能是a1的reference, s2=a2, 就是把a1=a2了?

【在 d*******d 的大作中提到】

:
: s1是a1的地址，s2是a1的reference,不能说s1 = s2.

d*d2007-11-19 08:11

6 楼

是谁的reference只能在定义的时候决定，然后就不能改了。
对。

【在 j*****k 的大作中提到】

: 那后面s2=a2了，就不是s2变成a2的reference了？
: 还是说s2就只能是a1的reference, s2=a2, 就是把a1=a2了?

j*g2007-11-19 08:11

7 楼

s2 is the reference of a1.
so s2=a2 ==> a1=a2 ==> *s1="World!"

c*x2007-11-19 08:11

8 楼

the answer is : world! world!

【在 m**g 的大作中提到】

: string a1 = "Hello";
: string a2 = "world!";
: string* s1 = 0;
: string& s2 = a1;
: s1 = &a1;
: s2 = a2;
: std::cout << *s1 << " " << s2 << std::endl;
: and why?