Cross-border access issues for new in C + + _c language

Today, when I hit the code, I found a bug to share with you, and I hope everyone will not commit the same mistake as me next time.

If you make the same mistakes as me, you can know where you are wrong! < (^) >

The function is as follows: (Implementation of the Fibonacci sequence)

Long long fibonacciseq (int n)
{
long long *fib=new long long[n+1];
Fib[0] = 0;
FIB[1] = 1;
for (int i = 2;i <=n; i++)
{
Fib[i] = fib[i-1] + fib[i-2];
Long LONG ret = fib[n];
Delete[] FIB;
return ret;
}

The above program has bugs, and if the argument to the function is 0, the program crashes because it triggers a breakpoint.

Single-step debugging, depending on the memory window will find the problem!

After the fib point to memory initialization is complete, its memory as shown above, we can observe this block of memory before and after FD FD FD, 0xFD for the initialization of protected memory (debug version in the dynamic allocation of memory before and after the memory to protect against cross-border access), while fib[1] = 1; The FD FD fd and the four bytes after it have been changed to 01 00 00 00 00 000000, as shown below:

The program ran to delete[] fib, only to find the "protected memory Flag" start location, another "protected memory flag" can not be found, so the program run will fail!

In fact, it is very simple, that is, cross-border access! I only new a piece of space, but saved two variables, of course not!