![Example:
struct Person
{
char name[50];
int citNo;
float salary;
};
Here, a derived type struct Person is defined.
Now, variables of this type can be created.](https://image.slidesharecdn.com/structuresunion-230419051943-2877ee05/85/STRUCTURES_UNION-pptx-3-320.jpg)
![Creating structure variables:
-When a struct type is declared, no storage or memory is allocated.
-To allocate memory of a given structure type and work with it, we need to
create variables.
• Example:
struct Person
{
char name[50];
int citNo;
float salary;
};
int main()
{
struct Person person1, person2,
p[20];
………..
return 0;
}
struct Person
{
char name[50];
int citNo;
float salary;
} person1, person2, p[20];
In both cases, two variables person1,
person2, and an array variable p
having 20 elements of type struct
Person are created.](https://image.slidesharecdn.com/structuresunion-230419051943-2877ee05/85/STRUCTURES_UNION-pptx-4-320.jpg)
![UNION:
-A union is a user-defined type similar to structs in C except for one key
difference.
-Struct allocate enough space to store all its members where as unions
allocate the space to store only the largest member.
EXAMPLE:
union car
{
char name[50];
int price;
};
The above code defines a derived type union car.](https://image.slidesharecdn.com/structuresunion-230419051943-2877ee05/85/STRUCTURES_UNION-pptx-6-320.jpg)
![Creating union variables:
-When a union is defined, it creates a user-defined type.
-To allocate memory for a given union type and work with it, we need to create
variables.
union car
{
char name[50];
int price;
};
int main()
{
union car car1, car2;
return 0;
}
union car
{
char name[50];
int price;
} car1, car2;
In both cases, union variables car1,
car2, and a union pointer car3 of
union car type are created.](https://image.slidesharecdn.com/structuresunion-230419051943-2877ee05/85/STRUCTURES_UNION-pptx-7-320.jpg)
![DIFFERENCE BETWEEN
STRUCTURE AND UNION
union unionJob
{
char name[32];
float salary;
int workerNo;
} uJob;
struct structJob
{
char name[32];
float salary;
int workerNo;
} sJob;
• Size of union = 32
• Size of structure = 40
The size of a union variable will
always be the size of its largest
element.
In the given example, the size of its
largest element, (name[32]), is 32
bytes.
With a union, all members share the
same memory.](https://image.slidesharecdn.com/structuresunion-230419051943-2877ee05/85/STRUCTURES_UNION-pptx-9-320.jpg)
STRUCTURES_UNION.pptx
- 2. STRUCTURES: -A structure is a collection of variables of different types under a single name. -To define a structure, the struct keyword is used. Syntax of structure: struct structureName { dataType member1; dataType member2; ... };
- 3. Example: struct Person { char name[50]; int citNo; float salary; }; Here, a derived type struct Person is defined. Now, variables of this type can be created.
- 4. Creating structure variables: -When a struct type is declared, no storage or memory is allocated. -To allocate memory of a given structure type and work with it, we need to create variables. • Example: struct Person { char name[50]; int citNo; float salary; }; int main() { struct Person person1, person2, p[20]; ……….. return 0; } struct Person { char name[50]; int citNo; float salary; } person1, person2, p[20]; In both cases, two variables person1, person2, and an array variable p having 20 elements of type struct Person are created.
- 5. Access members of a structure . - Member operator Suppose, you want to access the salary of person2. person2.salary
- 6. UNION: -A union is a user-defined type similar to structs in C except for one key difference. -Struct allocate enough space to store all its members where as unions allocate the space to store only the largest member. EXAMPLE: union car { char name[50]; int price; }; The above code defines a derived type union car.
- 7. Creating union variables: -When a union is defined, it creates a user-defined type. -To allocate memory for a given union type and work with it, we need to create variables. union car { char name[50]; int price; }; int main() { union car car1, car2; return 0; } union car { char name[50]; int price; } car1, car2; In both cases, union variables car1, car2, and a union pointer car3 of union car type are created.
- 8. Access members of a union -To access price for car1, car1.price is used.
- 9. DIFFERENCE BETWEEN STRUCTURE AND UNION union unionJob { char name[32]; float salary; int workerNo; } uJob; struct structJob { char name[32]; float salary; int workerNo; } sJob; • Size of union = 32 • Size of structure = 40 The size of a union variable will always be the size of its largest element. In the given example, the size of its largest element, (name[32]), is 32 bytes. With a union, all members share the same memory.