C Language Slides

1. Structures
• A structure is a collection of one or more variables types
grouped under a single name for easy manipulation.
• The variables in a structure, unlike those in an array, can
be of different variable types.
• A structure can contain any of C's data types, including
arrays and other structures.
• Each variable within a structure is called a member of
the structure.

4. Using a struct
• By defining a structure you create a new data
type.
• Once a struct is defined, you can create
variables of the new type.
Student stu_variable;

5. Accessing Structure Members
• Structure members are accessed using the
structure member operator (.), also called the dot
operator, between the structure name and the
member name.
• Thus variable s1 can be access in following way
S1.no=10;
S1.name=”AMAR”;
S1.per=80;
• printf("%d,%s,%f", s1.no, s1.name,s1.per);

6. #include <stdio.h>
struct student
{
int id;
char *name;
float per;
};
void main()
{
struct student st;
st.id=1; st.name=“ram”; st.per=90.5;
}

7. Advantage Of Using structure
• One major advantage is that you can copy
information between structures of the same type
with a simple equation statement.
• Continuing with the preceding example, the
statement
S2 = S1;
is equivalent to this statement:
S2.no=S1.no;
S2.name=S1.name;
S2.per=S1.per;

8. Arrays of Structures
#include <stdio.h>
struct entry
{
char fname[20];
};

9. main()
{ struct entry list[4];
for (i = 0; i < 4; i++)
{
printf("nEnter first name: ");
scanf("%s", list[i].fname);
}
for (i = 0; i < 4; i++)
{
printf("Name: %s ", list[i].fname,}
}

10. Pointer To Structure
struct emp
{ int empno;
char nm[20]; };
void main()
{
struct emp e1={10,”RAJ”};
struct emp *p;
p=&e1;
printf(“%d %s ”, e1.empno, e1.nm);
printf(“%d %s ”, p->empno, p->nm);
}

11. UNIONS
• A union is a variable which may hold members of
different sizes and types.
• The syntax for declaring a union is similar to that of
a structure:
union number
{
int number;
double floatnumber;
} anumber;

12. • This defines a union called "number" and a
variable of it called "anumber".
• Members of the union can be accessed in the
following way:
• printf("%f",anumber.floatnumber);
• When the C compiler is allocating memory for
unions it will always reserve enough room for
the largest member.