Operations on struct variables in C

1.9

In C, the only operation that can be applied to struct variables is assignment. Any other operation (e.g. equality check) is not allowed on struct variables.
For example, program 1 works without any error and program 2 fails in compilation.

Program 1

#include <stdio.h>

struct Point {
  int x;
  int y;
};

int main()
{
  struct Point p1 = {10, 20};
  struct Point p2 = p1; // works: contents of p1 are copied to p1
  printf(" p2.x = %d, p2.y = %d", p2.x, p2.y);
  getchar();
  return 0;
}



Program 2

#include <stdio.h>

struct Point {
  int x;
  int y;
};

int main()
{
  struct Point p1 = {10, 20};
  struct Point p2 = p1; // works: contents of p1 are copied to p1
  if (p1 == p2)  // compiler error: cannot do equality check for         
                  // whole structures
  {
    printf("p1 and p2 are same ");
  }
  getchar();
  return 0;
}

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