Why does this generate an error (Debug Assertion Failed)

[fl]

Hi,

When I try to run a snippet code from the web, it has a Debug Assertion
Failed error in MSVC. Specifically, when it is stepped into

b0=a0;

it jumps to the assign function

array &array::operator =(const array &rhs);

At line:
delete[] data;

the Debug Assertion Error pops.

I do not understand why it has such an error. Could you explain it to me?


Thanks,


/////////////
class array {
int tmp;

int *data;
size_t n;
public:
array(){
data=&tmp;
}
array &array::operator =(const array &rhs);
};

array &array::operator =(const array &rhs)
{
delete[] data;

n = rhs.n;
data = new int[n];
std::copy_n(rhs.data, n, data);

return *this;
}

int main () {
array a0;
array b0;

b0=a0;
return 0;
}

[fl]

The original code snippet does not have definition

int tmp;

inside class array. I added it to make

delete[] data;

work.

It is possible that data shouldn't be used in such a way. Then, how to use
data in the class array?


Thanks,

[fl]

Oh, I find the answer. The constructor can be:

public:
array(){
n=0;
data=new int[n];
}

Thanks,

[asetof...@gmail.com]

fl wrote:

#I write:
class array {
int tmp;

int *data;
size_t n;
public:
array(){
data=&tmp;
}
array &array::operator =(const array &rhs);
};

array &array::operator =( array &rhs)
{
delete[] data;
#in b0=a0
#for me, the first run time error
#is here because delete
#want to free &tmp
#and that address seems not be
#one new or malloc return