Question

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

Short answer

Answer: When we add 4 to a pointer to an int (ptr), the memory address stored in the pointer will increase by 4 times the size of an int (usually 16 bytes). Note that the actual size of an int may vary depending on the system.

Step-by-step solution

Understand pointers and pointer arithmetic

When we declare a pointer in C or C++ (in this case, a pointer to an int), we are essentially creating a variable that holds the address of another variable (the int in this case). Adding an integer value to a pointer (called pointer arithmetic) increases the memory address stored in the pointer by the size of the data type it points to, multiplied by the added value.

Consider the size of an int and pointer arithmetic

Based on the question, we know that ptr is a pointer to an int. In most systems, the size of an int is 4 bytes (it may vary in different systems). Adding 4 to the pointer means we want to add 4 times the size of an int (i.e., 4 * 4 bytes) to the memory address stored in the pointer.

Calculate the new memory address

As we concluded in the previous step, adding 4 to a pointer to an int will result in adding 4 * sizeof(int) bytes to the memory address stored in the pointer. So, if the initial address stored in ptr was x, the new address after the addition would be x + 4 * sizeof(int) bytes. In most systems, as sizeof(int) = 4 bytes, the new address will be x + 16 bytes.

Summarize the result

In conclusion, when you add 4 to a pointer to an int (ptr), the memory address stored in the pointer will increase by 4 times the size of an int (usually 16 bytes). It's important to note that the actual size of an int may vary depending on the system. So, always ensure to use sizeof() function to find the appropriate data type size for the particular system you're working on.