Struct assignment.

output

$ gcc struct.c -o struct
$ ./struct 
a.Bar: 1
b.Bar: 2
a.Bar: 2
b.Bar: 1

struct.c

#include "stdio.h"

typedef struct Foo {
  int Bar;
} Foo;

int main(int argc, char* argv[])
{
  // Init them. Plus c as a swap buffer.
  Foo a,b,c;
  
  a.Bar = 1;
  b.Bar = 2;

  printf("a.Bar: %d\n", a.Bar);
  printf("b.Bar: %d\n", b.Bar);

  // Flip them.
  c = a;
  a = b;
  b = c; 

  printf("a.Bar: %d\n", a.Bar);
  printf("b.Bar: %d\n", b.Bar);
}