How do I determine the size of my array in C?

To determine the size of an array in C, use the formula:

sizeof(array) gives the total memory size of the array, and sizeof(array[0]) gives the size of a single element. Dividing these provides the number of elements in the array. For example:

This works only for statically declared arrays, not for pointers or dynamically allocated arrays, as sizeof on a pointer only gives the size of the pointer, not the full array.