STRNCPY overwrites?

[D4rkZ3r0]

Hey there,

In the book it says the following code causes the new value of s to contain “Say Hi”, this string also displays onscreen because it is the value that strncpy() returns.

But rather it looks to me like it overwrites the first 2 chars in s with the first 2 chars in t, hence the y and the space after it showing up in the output.
Is the author of the book that I am reading wrong?

#include <iostream>
#include <cstring>
using namespace std;

int main(void)
{
	char s[7]= "Say ";
	char t[]="Hi";
	cout << strncpy(s, t, 2);
}

/*Output on my computer is:
Hiy Press any key to continue...
*/

The following code I wrote I think will do what the author is trying to do.

#include <iostream>
#include <cstring>
using namespace std;

int main(void)
{
	char s[7]= "Say ";
	char t[]="Hi";
	cout << strcat(s, t);
}

/*Output on my computer is:
Say HiPress any key to continue...
*/

[Peter87]

Yes you are right

[D4rkZ3r0]

Just checking, thanks for the info Peter! I can't believe this made it to the presses without being caught :P

[Disch]

You'd be surprised how much bogus/incorrect info gets published.

The thing is... editors are not programmers, so they don't really know whether the code is correct or not.

[Wisely Done]

You probably should use strncat instead of strcat as it's more safe due to having a length check.

[D4rkZ3r0]

Thanks for the tip, I was unaware of that function, since the book didn't mention it.