finding the size of an unknown array in C

Question

We have been given a large array of unknown size with elements given , is there any function or something other through which we can find the size of that array in language C int a[]={4,6,4,26,3,2,5,7,3,7,3,2,5,4,6,3,7,232,6,32,6,3,7,3,6,2,5,7,3,6,3,6,36,3,67,23,6};

int a[]={4,6,4,26,3,2,5,7,3,7,3,2,5,4,6,3,7,232,6,32,6,3,7,3,6,2,5,7,3,6,3,6,36,3,67,23,6}; — Azam, Aug 02 '18 at 18:50
#include It does not help either int main() {int a[]={4,6,4,26,3,2,5,7,3,7,3,2,5,4,6,3,7,232,6,32,6,3,7,3,6,2,5,7,3,6,3,6,36,3,67,23,6}; printf("%d",sizeof(a)); } — Azam, Aug 02 '18 at 18:55
In this way you get the size in bytes, to print the number of elements use `printf("%zu\n", sizeof(a) / sizeof(*a));` — David Ranieri, Aug 02 '18 at 18:56
@Azam It is known, it just isn't readily apparent. By contrast, if you were to pass that array in as an argument to a function, then as far as that function was concerned, the size of the array would be unknown as it would decay to a pointer and thus `sizeof` would give you the size of the pointer and not the number of bytes in the array. — Christian Gibbons, Aug 02 '18 at 18:58
if you dont have an array, but just a degenerate array, which doesn't have a length you will have to null terminate it and iterate it — Grady Player, Aug 02 '18 at 19:23
Upvoting to offset some of the unexplained, and thus unhelpful, downvotes. — Richard, Aug 02 '18 at 20:10

score 1 · Answer 1 · answered Aug 02 '18 at 18:55

1

The size in bytes you can get by

sizeof(a);

The number of elements in that array you can get by

sizeof(a)/sizeof(a[0]);

answered Aug 02 '18 at 18:55

Yunnosch

26,130
9
42
54

finding the size of an unknown array in C

1 Answers1