Structure in c S-Teacher

1. Structure
Structures are user defined data types
It is a collection of heterogeneous data
It can have integer, float, double or character data in
it
We can also have array of structures
struct <<structname>>
{
members;
}element;
We can access element.members;

2. Example
struct Person
{
int id;
char name[5];
}P1;
P1.id = 1;
P1.name = “vasu”;

3. typedef statement
User Defined Data Types
The C language provides a facility called typedef for
creating synonyms for previously defined data type names.
For example, the declaration:
typedef int Length;
makes the name Length a synonym (or alias) for the data
type int.

4. typedef(contd.)
The data “type” name Length can now be used in
declarations in exactly the same way that the
data type int can be used:
Length a, b, len ;
Length numbers[10] ;

5. UNION

6. UNION
Union has members of different data types, but can
hold data of only one member at a time.
The different members share the same memory
location.
The total memory allocated to the union is equal to
the maximum size of the member.

7. EXAMPLE
#include <stdio.h>
union marks
{
float percent;
char grade;
};
int main ( )
{
union marks student1;
student1.percent = 98.5;
printf( "Marks are %f address is %16lun", student1.perc
ent, &student1.percent);
student1.grade = 'A';
printf( "Grade is %c address is %16lun", student1.grade,
&student1.grade);
}

8. ENUM

9. ENUMERATED DATATYPE
Enumeration is a user-defined data type. It is
defined using the keyword enum and the syntax
is:
enum tag_name {name_0, …, name_n} ;
The tag_name is not used directly. The names in
the braces are symbolic constants that take on
integer values from zero through n.

10. Enumerated(contd.)
As an example, the statement:
enum colors { red, yellow, green } ;
creates three constants.
red is assigned the value 0,
yellow is assigned 1 and
green is assigned 2.