initialization of structure members in c programming Language.

Copy Structure:
From the given figure we can say that the Structure can be copied in different ways.
1.Copy structure attribute by attribute into another structure.
2.Deep Copy of struct in C.
3.Shallow Copy of struct in C.
Before to proceed first of all let learn what is Deep Copy and Shallow copy in C language.

Deep Copy: Copying the specific content of the object is know as deep copy. Deep copy creates a new memory address in the computer to store the copied object. Changes to the original source data do not affect the copied or replicated data.
Shallow Copy:The copy that you get from an assignment statement with a structure variable is a bit-for-bit copy, also called a shallow copy.


1. Copy attribute by attribute of struct into another struct.
This approach of copying structure is veary simple. In this aproach we copies structure attribute by attribute into another structure.
This approach of copying struture become more difficult to manage and typing.
Following is the program to demonstrate copying structure attribute by attribute.

/*copy structure attribute by attribute into another structure*/
#include <stdio.h>
#include <string.h>
typedef struct employee {
 int empno ;
 char name [ 40 ];
 char gender[10];
 float salary;
}Emp;
void print_emp(Emp *e1)
{
  printf("\n(Empno: %d, Ename: %s, Gender: %s, Salary: %.2f )",
e1->empno,e1->name,e1->gender,e1->salary);
}
int main ( )
{
   Emp user={100,"Kailas","Male",45000},user1;
  /* copy structure atteibute by attribute */
   user1.empno=user.empno;
  strncpy(user1.name,user.name,sizeof(user.name));
  strncpy(user1.gender,user.gender,sizeof(user.gender));
  user1.salary=user.salary;
  printf("\n Employee: ");
  print_emp(&user);
  printf("\n Employee Copy: ");
  print_emp(&user);
   return (0);
}


Output:
Employee: (Empno:100, Ename:Kailas, Gender:Male,Salary:45000)
Employee copy: (Empno:100, Ename:Kailas, Gender:Male,Salary:45000)


3.Shallow copy.

 /**  3.Shallow Copy of struct in C **/
#include <stdlib.h>
#include<stdio.h>
#include <string.h>
typedef struct student
 {
  char *name;
  int sid;
    float per;
 }student;
 int main()
 {
  student s1;
  s1.name = (char*)malloc(25);
  strcpy(s1.name, "Sachin");
  s1.sid = 22;
   s1.per=89.00;
  student s2 = s1;
   printf("\n Student Info\n");
  printf(" %d %s %.2f",s2.sid, s2.name, s2.per);
 if (s1.name != NULL)
 {
   free(s1.name);
   s1.name = NULL;
 }
 return 0;
}
Output:
Student Info
22 Sachin 89.00

2. Deep copy

#include <string.h>
#include <stdio.h>
typedef struct Employee
 {
   char *name;
   int empno;
 }emp;
int main(int argc, char *argv[])
 {
   emp e1;
   emp e2;
  e1.name = (char *)malloc(10);
  e1.empno = 20;
  strcpy(e1.name, "Raviraj");
   printf("Empno: %d name: %s, \n", e1.empno, e1.name);
  e2 = e1;
     strcpy(e2.name, e1.name);
  printf("Empno: %d e2->name: %s\n",e2.empno, e2.name);
  free(e1.name);
  free(e2.name);
  return 0;
 }
Output:
Empno: 20 name:Raviraj
Empno: 20 e2->name:Raviraj

Compare structure in C programming.

1.Both Structure Variable have the Same Value.
This is the safe way to compare the structure members by member for the equality.

/*Compare the the structure variable when Both have the same value*/
#include <stdio.h>
struct person
{
  int pid;
  char G;
};
  int main()
{
  struct person p1, p2;
  /*Assigning value to the p1*/
  p1.pid = 1;
  p1.G ='M';
  /*Assigning value to the p2*/
  p2.pid = 1;
  p2.G ='M';
  //Comparing the structure variable
  if((p1.pid == p2.pid) && (p1.G == p2.G))
  {
   printf("Struct variables are equal\n");
  }
  return 0;
}
Output: Struct variables are equal

2.Both Structure Variable don't have the Same Value.
This is the another way to compare the structure members.

/*Compare the the structure variable when Both structure don't have the same value*/
#include <stdio.h>
struct person
 {
  int pid;
  char G;
 };
  int main()
 {
  struct person p1, p2;
  /*Assigning value to the p1*/
  p1.pid = 21;
  p1.G ='F';
  /*Assigning value to the p2*/
  p2.pid = 11;
  p2.G ='M';
  //Comparing the structure variable
  if((p1.pid == p2.pid) && (p1.G == p2.G))
  {
   printf("Struct variables are equal\n");
  }
  else
  {
   printf("Struct variables are not equal\n");
  }
  return 0;
 }
Output:
Struct variables are not equal.

Previous Topic:-->>Structure Initialization in C || Next topic:-->>Array of Structure.

Other Topics:
Variables and Identifiers  Relational Operators   if-else statements  Switch case   While Loop   Infinite while Loops  C FOR Loop  Infinite for Loops   Continue in Loops   One Dimensional Array  Two Dimensional Arrays  Read and Display 2D Arrays  Types of functions  Passing Array To Functions  Nesting of Function  Array vs Structure  Array of Structure  Structures and Functions  Structures Within Structures  Use Of Pointers In C  File Handling In C  Loops FAQ  Arrays FAQ  count vowels in a file  Function FAQ   Conditional Statements Assignments  For Loops Assignments  Arrays Assignments  Function Assignments  Structure Assignments  Pointers Assignments  Files Assignments  Storage classes Assignments  Binary Files  count words,lines in a file  Copy files  Update File  Continue in Loops   break in Loops   Difference Between While and Do while  difference while do..while & for   malloc  calloc  Storage Classes  Operators MCQ  Conditional Statements MCQ  Loops MCQ  Arrays MCQ  Function MCQ  Structure MCQ  Pointers MCQ  Files MCQ  Storage classes MCQ