Difference between struture and union in C Language

STRUCTURES	UNION
Struct keyword is used to declare the structure	Union keyword is used to declare the Union
Structure variable will allocate memory for all the structure members separately.	Union variable will allocate common memory for all the union members.
Example: struct Employee{ int age; char name[50]; float salary; };	Example: union Employee{ int age; char name[50]; float salary; };
Structures will occupy more memory space.Memory_Size = addition of all the structure members sizes. Memory_Size = int + char array [50] + float Memory_Size = 2 + 50 + 4 Bytes Memory_Size = 56 Byte	Union will occupy less memory space compared to structures.Memory_Size = Size of the largest Union member. From the above example, Largest Union member is char array so, Memory_Size = 50 Bytes
It allows us to access any or all the members at any time.	It allows us to access only one union member at a time.

C Program to find Difference between Structure and Union

In this program, we are going to declare the structure and union with same data type members and then we are going to calculate the size of union and structure using sizeof function.

CODE

/* C Program to find difference between Structure and Union */

#include <stdio.h>

struct Employee

{

  int age; 

  char Name[50];

  char Department[20];

  float Salary;

};

union Person

{

  int ag; 

  char Nam[50];

  char Departent[20];

  float Salar;

};

int main()

{

  struct Employee emp1;

  union Person Person1;

   

  printf(" The Size of Employee Structure = %d\n", sizeof (emp1) );

  printf(" The Size of Person Union = %d\n", sizeof (Person1));

  return 0;

}