What are the key differences between pointers and arrays in C language?

What are the key differences between pointers and arrays in C language?

Core Differences:

1. Memory Allocation

   • Arrays allocate contiguous memory space on stack or static storage
   • Pointers are variables storing address information, can point to any memory location

2. sizeof Operator

   c
   int arr[10];
   int *ptr = arr;
   sizeof(arr);  // Returns 40 (10 * sizeof(int))
   sizeof(ptr);  // Returns 8 (pointer size on 64-bit system)

3. Assignment Operations

   • Array names cannot be assigned, are constant addresses
   • Pointers can be reassigned to point to different addresses

4. Operator Precedence

   • Array subscript [] has higher precedence than dereference *
   • *ptr++ dereferences then increments pointer
   • (*ptr)++ increments the value pointed to

5. Parameter Passing

   • Arrays decay to pointers when passed as parameters
   • Cannot determine actual array size inside function

Common Pitfalls:

• Confusing type differences between &arr and arr
• Misusing pointer arithmetic causing out-of-bounds access
• Forgetting array names decay to pointers in expressions