So, the key thing to remember is that a pointer is just a word-sized variable that's typed for dereferencing. That means that whether it's a void *, int *, long long **, it's still just a word sized variable. The difference between these types is what the compiler considers the dereferenced type. Just to clarify, word sized means width of a virtual address. If you don't know what this means, just remember on a 64-bit machine, pointers are 8 bytes, and on a 32-bit machine, pointers are 4 bytes. The concept of an address is SUPER important in understanding pointers. An address is a number capable of uniquely identifying a certain location in memory. Everything in memory has an address. For our purposes, we can say that every variable has an address. This isn't necessarily always true, but the compiler lets us assume this. The address itself is byte granular, meaning 0x0000000 specifies the beginning of memory, and 0x00000001 is one byte into memory. This means that by adding one to a pointer, we're moving one byte forward into memory. Now, lets take arrays. If you create an array of type quux that's 32 elements big, it will span from the beginning of it's allocation, to the beginning of it's allocation plus 32*sizeof(quux), since each cell of the array is sizeof(quux) big. So, really when we specify an element of an array with array[n], that's just syntactic sugar (shorthand) for *(array+sizeof(quux)*n). Pointer arithmetic is really just changing the address that you're referring to, which is why we can implement strlen with
while(*n++ != '\0'){
len++;
}
since we're just scanning along, byte by byte until we hit a zero. Hope that helps!
