why this code give error

[gurpartap]

Error: Segmentation fautlt

  #include <stdio.h>

void main()
{
int arr[5] = {1,2,3,4,5};
int *ptr ;
*ptr = *(arr + 2);
//ptr ++ ; 
printf("VAlue = %d\n",*ptr);
}

[integralfx]

int *ptr ;
ptr is uninitalised which means it contains some garbage value.

*ptr = *(arr + 2);
Dereferencing a garbage value will lead to undefined behaviour, usually program crashing. You're trying to access memory that you don't have permission to, resulting in a segmentation fault.

[Peter87]

If you want ptr to point to the third element in the array you should have written

ptr = arr + 2;

or

ptr = &arr[2];

[gurpartap]

thanks @integralfx and @Peter87 for clarification.
Another solution is :
ptr = malloc(4);
then
*ptr = *(arr + 2) ;

[integralfx]

Another solution is :
ptr = malloc(4);
then
*ptr = *(arr + 2) ;

I thought you were using ptr, to access arr's elements? If so, there is no need to dynamically allocate memory. You can just assign ptr to arr.

[Peter87]

If you want to store a copy of the array element, why not simply store it in a regular int variable?