Question

Assuming that ptr is a pointer to an int, what happens when you add 4 to ptr?

Short answer

Based on the above step by step solution, here's a short answer: When adding 4 to a pointer (ptr) to an integer (int), the pointer will advance 4 int elements (16 bytes, assuming an int is 4 bytes) forward in the memory. For example, if ptr initially points to the memory address 0x1000, adding 4 to ptr will update its value to 0x1010, making it point to the memory location 4 int elements after the original one.

Step-by-step solution

Understand the pointer and its initial state

A pointer is a variable that stores a memory address. In this case, ptr is a pointer to an int, meaning it stores the memory address of an integer. Let's assume the initial memory address stored in ptr is 0x1000 (for illustration purposes only, real addresses might be different).

Visualize memory locations

It's important to remember that in most systems, an int takes up 4 bytes of memory. So, if the starting memory address is 0x1000 (initial value of ptr), the next int would be stored at address 0x1004, then 0x1008, and so on.

Add 4 to the pointer

Adding 4 to ptr means advancing the pointer 4 elements ahead. So instead of pointing to the memory address 0x1000, it will point to address 0x1000 + (4 * sizeof(int)). As sizeof(int) is 4 bytes in most systems, ptr would now point to the address 0x1000 + (4 * 4) = 0x1010.

Analyze the result

After adding 4 to ptr, it now points to the memory address 0x1010, which is 4 elements or 16 bytes after the original memory location. In summary, when we added 4 to ptr, it advanced the pointer 4 int elements forward in the memory.