Initialize/reset struct to zero/null

Question

struct x {
    char a[10];
    char b[20];
    int i;
    char *c;
    char *d[10];
};

I am filling this struct and then using the values. On the n

Answer 1

You can use memset with the size of the struct:

struct x x_instance;
memset (&x_instance, 0, sizeof(x_instance));

Answer 2

Define a const static instance of the struct with the initial values and then simply assign this value to your variable whenever you want to reset it.

For example:

static const struct x EmptyStruct;

Here I am relying on static initialization to set my initial values, but you could use a struct initializer if you want different initial values.

Then, each time round the loop you can write:

myStructVariable = EmptyStruct;

Answer 3

If you have a C99 compliant compiler, you can use

mystruct = (struct x){0};

otherwise you should do what David Heffernan wrote, i.e. declare:

struct x empty = {0};

And in the loop:

mystruct = empty;