why does this code give a access violation when run on msdev ?

Question

while(*a++ = *b++){} where a and b are valid char pointers.

Answer 1

The strings pointed to may not be null terminated meaning data is being read from and assigned to memory it should not have access to, hence the violation.

Answer 2

If b is a 10 character null terminated string and a is a buffer where 4 chars has been allocated, you'll write outside of allocated memory using the above code.

Answer 3

It looks like memory allocated for array 'a' is less than the length of the array 'b'.

Answer 4

One alternative answer:

char *a = "Hello";
char *b = "World";

These are both valid char pointers. But a does not point to writable memory.

Answer 5

If you're running it on MSDev, bung it in the debugger and step through it, and/or have a look at the actual memory areas where a and b are stored and see directly what's going on. It could be any of the things already mentioned as possibilities.