Question

I have an int array and I need to find the number of elements in it. I know it has something to do with sizeof but I’m not sure how to use it exactly. example

 int data2[]={a,b,c,d};

Answer 1

With an array you can do:

int numElements = sizeof(data) / sizeof(data[0]);

But this only works with arrays, and won’t work if you’ve passed the array to a function: at that point the array decays to a pointer, and so sizeof will return the size of the pointer.

You’ll see this wrapped up in a macro:

#define ARRAY_LENGTH(x) (sizeof (x) / sizeof (x)[0])