Any problem in this code?

Question

1.00/5 (1 vote)

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const char* append(const char* s1, const char* s2) {
string s(s1);
s += s2;
return s.c_str();
}

void foo() {
const char* total = append("abc", "def");
}

What I have tried:

Please let me know if there is any problem in this code?

Posted 13-May-18 7:40am

kishore kumar mishra

Updated 14-May-18 3:32am

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Mehdi Gholam 13-May-18 13:58pm

Does it work?

[no name] 13-May-18 14:03pm

It works still there is some bug in this which I am not able to find out.

2 solutions

Solution 2

Because the scope of the string s is only within the function append. As soon as that function returns, the string destructor will be called and the memory containing the characters released. That means that the space that was occupied may immediately be overwritten by some other data.

Posted 14-May-18 3:32am

Richard MacCutchan

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KarstenK · Accepted Answer · 2018-05-13T08:08:00

Solution 1

It is a mistake ~~really no good style~~ to return the pointer of a deallocated object when the functions scope is left. In such a simple scenario (string class) it may work, but it is wrong. Some destructors may delete that pointed resource and you have a crash.

The function makes no sense, because the operation can be written in a line.

Posted 13-May-18 8:08am

KarstenK

Updated 14-May-18 1:28am

v2

Comments

CPallini 13-May-18 16:40pm

5.I would call 'mistake', such 'bad style'.

KarstenK 14-May-18 7:29am

Ofcourse you are right. => Corrected