In C, what happens in memory when we do cast int to struct*? -

typedef struct block {    size_t size;    struct block* next; } node;  static char arr[1000]; 

what happens arr

when do

node* first_block = (node*)arr; 

?

i understand equal to

node* first_block = (node*)&arr[0]; 

but

sizeof(node) = 8; sizeof(arr[0])= 1; 

so first element override next 7 elements in arr, because it's struct ? can explain me cast, please ?

when write

node* first_block = (node*)arr; 

you not changing in memory, pointer area in memory, type of pointer determines how area treated in regard pointer arithmetic.

first_block->next pointer determined characters in array.

as comparison have char* pointer same array

(if arr declared @ global scope contain 0's)

char* q = arr; node* p = (node*)arr;                   arr[1000]           +----------------------+   q  ->   |   |   |          |   |           | 0 | 0 | ...      | 0 |   p ->    |   |   |          |   |           +----------------------+ 

when do

q = q + 1;    // move character pointer 1 char forward since q char pointer 

when do

p = p + 1;    // move node pointer sizeof(node) chars forward since p node pointer 

when *q character value of q points to, *p gives node value char arr, i.e. characters interpreted node struct.