Question

I am wondering if this would cause a memory leak or an undefined outcome in C++?

string foo()
{
    char tempArray[30];
    strcpy(tempArray, "This is a test");
    return string(tempArray);
}

I know this is a bad thing in C but I haven’t found a definite answer for C++.

So everyone is saying no, but I am still confused as to when the memory is deallocated?

Lets say I have this method that calls the above method

void bar()
{
    string testString = foo();
}

At what point in the above code does the string object returned from foo() call its destructor? Is it immediately after getting copied into the object testString?

Answer 1

What happens in your example is that the constructor with the signature

string ( const char * s );

is called. The constructor allocates new memory for a copy of the string and copies it to that new memory. The string object is then responsible for freeing its own memory when its destructor is called.

When you make a copy of a string, the copy constructor also allocates memory and makes a copy.

You should also take a look at the RAII pattern. This is how string‘s memory management works.