Error while printing the address of array elements in C - c

Question

I have an error message:
cannot increment value of type int[2]
Is that because the size of int or what?
int arr[2]={10,20};
printf("%p \t %p \t",arr,++arr);

Answer 1

The only reason you are not able to modify its value is once you define a static array with n size then a variable name given to it is treated as constant pointer (Whose value can't be changed).
This restriction is imposed by the compiler because it thinks if you change the value arr then there no way to ensure the accuracy of the program because the base address has been modified
But if you really want to play with the pointers then check these codes:
int main() {
int arr[] = {1,2,3,0};
int *ptr = arr;
while(*ptr != 0) {
printf("%i ",*ptr);
ptr++; // or ++ptr;
}
return 0;
}
Output: 1 2 3
int main() {
int *arr = (int*)malloc(4*sizeof(int));
arr[0] = 1;
arr[1] = 2;
arr[2] = 3;
arr[3] = 0;
while(*arr != 0) {
printf("%i ",*arr);
arr++;
}
return 0;
}
Output: 1 2 3
I hope i made myself clear. Any doubt most welcome.

Answer 2

Please note that you are trying to modify address of array.
Consider:
printf("%p \t %p \t",arr,++arr);
I think you want to print the address of the array element at 2nd position(index 1).
To print the address if arr[1] you can try:
&a[1]
(a+1)
use pointers
use dynamically allocated arrays
#define ARRAY_COUNT 10
int main() {
int *arr = (int*)malloc(ARRAY_COUNT*sizeof(int));
while(*arr != 0) {
printf("%p ",arr);
arr++;
}
return 0;
}
Final Code:
#include <stdio.h>
int main()
{
int arr[2]={10,20};
int *ptr=arr;
printf("%p \t %p \t\n",ptr,ptr+1);
printf("%p \t %p \t\n",arr,arr+1);
printf("%p \t %p \t\n",arr,&arr[1]);
return 0;
}
Sample Output:
sh-4.3$ gcc -o main *.c
sh-4.3$ main
0x7fffdf064110 0x7fffdf064114
0x7fffdf064110 0x7fffdf064114
0x7fffdf064110 0x7fffdf064114
Also note that the statement:
printf("%p \t %p \t",arr,++arr);
is an Unspecified or Implementation-specific behavior since it can (and does) produce different results on different machines. To be concise, the order(left to right or otherwise) of passing the arguments to functions is not strictly specified by C.
Here:
printf("%p \t %p \t",arr,++arr);
Case 1: Left to right parameter passing causes arr address(address of a[0]) to be printed first and then incremented to print the next address(address of a[1])
Output:
0x7fffdf064110 0x7fffdf064114
0x7fffdf064110 0x7fffdf064114
0x7fffdf064110 0x7fffdf064114
Case 2: Right to left parameter passing causes arr address to be incremented first and printed (address of a[1]) and then print the address(address of a[1])
Output:
0x7fffdf064114 0x7fffdf064114
0x7fffdf064114 0x7fffdf064114
0x7fffdf064114 0x7fffdf064114