Structures and unions

Structures and unions are data types  that allow you to group different variables together under a single name. They are commonly used in programming languages like C and C++.

Structures

A structure is a collection of multiple variables of different data types grouped together under a single name. Each variable within a structure is known as a member or field. The structure provides a way to organize related data and manipulate it as a single unit.

To declare a structure in C, you use the 'struct' keyword followed by the structure name and a list of member variables inside curly braces.

The syntax to define a structure is as follows:

struct structure_name {

    type member1;

    type member2;

    // ...

};

Here's an example:

To define a structure variable, you use the structure name followed by the variable name:

struct Person person1;

Accessing Structure Members

To access structure members, you use the dot (.) operator. Here's an example:

Arrays of Structures

You can create arrays of structures by declaring the structure type and specifying the number of elements in square brackets. 

Here's an example:

O/p:-

Name: John

Age: 25

Height: 175.5

Nested Structures

Structures can be nested within other structures, allowing you to create more complex data structures. 

Here's an example:

Unions and Their Usage

A union is similar to a structure in that it allows you to combine multiple variables of different types into a single unit. However, unlike structures, unions can only hold one value at a time, representing different interpretations of the same memory space.

Here's an example:

Unions are useful in situations where you need to store different types of data in the same memory location, and you know that only one member will be used at a time.

It's important to note that unions can lead to issues if the correct member is not used to interpret the data. Care should be taken to ensure the proper use of unions to avoid unexpected behavior or memory-related problems.