Default Copy Ctor

[giles]

Below code when run causes a crash. why?

#include <string>

using namespace std;

int main()
{
string name = 0;
return 0;
}

TIA,
Giles

 

[Rolf Magnus]

Below code when run causes a crash. why?

#include <string>

using namespace std;

int main()
{
string name = 0;

This is equivalent to:

string name(string((const char*)0);

And the behavior is undefined if you provide a null pointer as argument to
the constructor that takes a const char*. If you want an empty string, just
write:

string name;

 

[Jürgen Devlieghere]

or if you want to see it explicitly

string name = "";

 

[ulrich]

Below code when run causes a crash. why?

#include <string>

using namespace std;

int main()
{
string name = 0;
return 0;
}

you are assigning a number to a string.

possibly, what you wanted to do is string name = "";
still, this is superfluous, because a string object is empty by default.

if you want to know exactly what's going on, step into it with your
debugger...

 

[Ron Natalie]

you are assigning a number to a string.

Nope: You're not assigning anything, this is
initialization syntax. Further, there is no conversion
of a number to string. What exists is a converting constructor
of type const char*, which this null pointer constant matches.
However that value yields undefined behavior when used to initialize
a string.