Arrays vs pointers

[4c0]

Hello everyone,im a beginner in C programming.I've read a lot about the differences between arrays and pointers and I'm pretty confused.
First of all what is the name of an array???
Is it a label (or an alias) to the memory address or constant pointer?

#include <stdio.h>
int main()
{
    char arr[] = "string";
    char* ptr = arr;

    printf("%c %c\n", arr[4], ptr[4]);
    printf("%c %c\n", *(arr+2), *(ptr+2));

    return 0;
}

What is the difference between *(arr+2) and *(ptr+2)?Does this have the same meaning to the compiler?
Thanks in advance for your answer.

[dwks]

The name of an array by itself is basically the same as "&array[0]": in other words, in most contexts it's treated as a pointer to the first element of the array. There are some cases when this is different (e.g. sizeof(array) will tell you the total bytes the array takes up, while sizeof(&array[0]) will tell you the size of pointers on your machine), but it's a useful simplification to think about. We sometimes talk about an array "degrading" to a pointer, since an with an array you have more information (e.g. the size) than you do with a pointer; this happens when, for example, you pass an array to a function and it becomes a pointer. Or, in your case, you assign a pointer to point at an array.

An array is basically a contiguous chunk of memory somewhere. When you say array[1], array[i], the compiler knows you mean to find that chunk of memory and grab that element. But a pointer is slightly different: there is a location somewhere in memory that is storing *an address*. So "char *ptr" itself must be given some space. When you say ptr[2] or *(ptr+2), the compiler does some math to figure out where you mean, based on the address stored in the pointer. Another way of looking at it is that if you had an array of zero elements (which is probably invalid), it wouldn't actually take up any space at all. Whereas every time you add a pointer, a little bit of space must be used to store the "value" of the pointer (which is itself an address).