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carraysmemset

Properly clearing an array

I've seen two different ways to fill a char[] with 0 (in this example, upon initialization):

/* method 1 */
char foo[1024] = {0};

/* method 2 */
char foo[1024];
memset(foo, '\0', sizeof(foo));

What are the main differences between the two codes? How do they differ in functionality, etc?

Solution

  • What are the main differences between the two codes?

    In case 1 the array is zeroed out from the moment it can be used, as it got initialised.

    In case 2 its content is well defined only after the call to memset().

    The essential difference is that for case 2 there is is gap where foo's content is "garbage". This isn't the case for case 1.