advanced patterns with Struct Copying in C - Overwriting Fields
Can someone help me understand I'm working on a C program where I define a struct to represent a 2D point and then try to copy it using a simple assignment. However, I'm working with unexpected behavior where the fields seem to get overwritten unintentionally. Here’s the structure definition: ```c typedef struct { int x; int y; } Point; ``` In my main function, I instantiate a `Point` and then create a copy of it: ```c int main() { Point p1 = {10, 20}; Point p2; p2 = p1; // Copying the struct p1.x = 30; // Modifying p1 after the copy printf("p1: (%d, %d)\n", p1.x, p1.y); printf("p2: (%d, %d)\n", p2.x, p2.y); return 0; } ``` I expected `p2` to retain the values of `p1` before the modification, but when I run the code, I see the output as: ``` p1: (30, 20) p2: (30, 20) ``` It seems like both `p1` and `p2` are pointing to the same memory location, which shouldn’t happen with a struct copy. I’ve also tried using `memcpy` in case there was some scenario with the assignment operator: ```c memcpy(&p2, &p1, sizeof(Point)); ``` However, the behavior remains the same. I’m using GCC version 11.1 on a Linux machine. Can someone guide to understand why this is happening? Is there something wrong with my code, or is there a better way to copy structs in C? Any insights would be appreciated! Thanks in advance!