Structure in C programming
How to create a structure?
How to declare structure variables?
How to initialise structure elements?
How to access structure elements?
Structure with structure / nested structure
Structure and pointer
Structure :: typedef keyword
Copy a structure into another structure
Structure:-
- Structure define using struct keyword.
- When a variable is associated with a structure the compiler allocates the the memory for each member. the size of structure is greater than or equal to the sum of size of its member.
- Each member within structure is assigned unique storage area of structure.
- Individual members can be accessed at a time.
- How to create a structure:-
using the struct keyword can create complete data structure in C.
Syntax:
Struct <StructName>
{
// Variables
.......
}
You can declare variables that have as type that structure by adding them after the closing curly bracket before the semicolon.
Ex.
Struct StructDemo
{
int age;
char *name;
} mark;
- How to declare structure variable :-
Memory will be allocated only if a variable is a declared for structure.
a structure variable can either be declared with the structure declaration or as a separate declaration like basic type.
Basic data types:-
Struct Demo{
int a, b;
};
int main ( )
{
Struct Demo var;
}
- How to any slide structure members:-
Memory is allocated only when variable are created, structure members can be initialised using curly brackets/ braces '{ }' .
Ex.
Struct StructDemo
{
int a, b,c;
};
int main ( )
{
Struct StructDemo Var= { 2,7,99};
}
- How to access structure elements:-
Structure members are accessed using dot (.) operator.
Syntax:
Structure Variable Name.MemberName;
Ex.
#include<studio.h>
Struct StructDemo
{
int a, b, c;
};
int main ()
{
Struct StructDemo Var = { 9, 99, 999};
Var.a = 999;
Var.c = 9;
printf (" a=%d, b=%d, c=%d", Var.a , Var.b, Var.c );
return 0;
}
- Structure within structure:-
Its also called as nested structure.
structure within structure means nested of the structure where one struct variable is used in another structure definition for a new structure is define inside the structure.
Ex.
Struct Studentdetails
{
char name[30];
char address [50];
Struct {
int marks;
int id;
}Strudent_details;
}
- Structure and pointer:-
A structure can contain pointers as structure members. You can create an invoice structure that contains invoice_number as a pointer:
struct invoice{
char* invoice_number;
char date[20];
};
struct address billing_addr;
struct address *pa = &billing_addr;
- Structure :: typedef keyword:-
We use the typedef keyword to create an alias name for data types. It is commonly used with structures to simplify the syntax of declaring variables.
Ex.
struct Distance{
int feet;
float inch;
};
int main() {
struct Distance d1, d2;
}
- Copy a structure into another structure
One of major advantage of structure is that you can copy it with the assignment ( =) operator:
struct_intance1 = struct_intance2
Notice that some old C compilers may not support structure assignment so you have to assign each structure member one by one.
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