Re: When you declare an array of chars and store a string in it, where is the position of the null character \0? And what happens to the unused memory locations?

Gary wrote:

> When you declare an array of chars and store a string in it, where is
> the position of the null character \0? 

After the last character of string data.

> And what happens to the unused
> memory locations?

They are set to zero.

> #include <stdio.h>
> int main(void)
> {
> char gstring2[25] = "dudes";
> gstring2[5] = 'a';
> printf("%s \n", gstring2);
> return 0;
> }
> 
> The output of main function was
> 
> dudesa

You overwrote the null terminator with a character.

> How come this code works,

Because there were extra characters that were set to zero due to the
partial initialization.

> and the statement
> gstring2[5] = 'a';
> doesn't overwrite the null character?

It did, but a new terminator was in place.

If you had this:


char str[] = "dudes";

Then you'd probably be in trouble. The next adjacent byte wouldn't even
belong to your object so overwriting the null terminator would cause
undefined behavior as soon as you tried a string operation.



Brian