C Programming: Learning about memory

Malloc is used to allocate memory to the heap, and needs to be unallocated with free().  Lifetime is as long as you want it to be.

With the array, it's allocated on the stack, and memory is automatically reclaimed once you lose scope.

Some good reading on this here:
<<Link to competing site removed>>

Mind = Blown (in regard to how the = is not treated the same way in those two scenarios)

char str[1000];

Please confirm if this is true: After the above command, the char array would have { '\0', '\0', '\0', ... , '\0' }.

char *str = malloc ( 1000 * sizeof(char) );

This char array would also have { '\0', '\0', '\0', ... , '\0' }. Can I call this an array?

So as Sara mentioned, the below would be the correct way:

char str[1000];
strcpy(str, "abc"); 

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Then please confirm if this is true: the char array would have { 'a', 'b', 'c', '\0', junk, junk, ... , junk } ? How did the '\0' get in there? Is that a feature of strcpy() -- it automatically appends '\0' ?

In addition to what kaufmed has stated, you still have to be careful with strncpy too. True, it will limit the number of bytes/chars that it will copy (so that you are protected if the input string in NOT null-terminated). However, if while copying this limit IS reached, it will NOT append a null char itself. So due to this, you can actually create a situation where the resultant string is NOT null-terminated. Therefore, when using strncpy, you still have to manually ensure that the result is definitely null-terminated.