Structures in C: An Introduction

In this tutorial, we will introduce Structures in C, a significant feature that brings together different data types under one roof, helping to make the programming language powerful and flexible. Structures are an integral part of C, and it's essential to grasp this topic to progress in your C programming journey.

Let's get started!

What is a Structure?

A structure is a collection of variables under a single name. These variables can be of different types, and each one is called a member or a field of the structure. The members of a structure are stored in contiguous memory locations, which means that they all share the same memory address.

Defining a Structure

To define a structure, you use the struct keyword, followed by your defined structure name and the variables inside curly brackets {}. Here is the syntax:

struct structureName {
   dataType member1;
   dataType member2;
   ...
};

For example, let's define a structure named Student:

struct Student {
   char name[50];
   int roll;
   float marks;
};

In the Student structure, name, roll, and marks are members of the structure.

Declaring Structure Variables

We can declare structure variables in two different ways:

1. When the structure is defined:

struct Student {
   char name[50];
   int roll;
   float marks;
} s1, s2;

In this case, s1 and s2 are variables of the structure type Student.

2. After the structure is defined:

struct Student {
   char name[50];
   int roll;
   float marks;
};

struct Student s1, s2;

Accessing Structure Members

To access the members of a structure, we use a dot . operator, also known as the structure member operator. Here is the syntax:

structureVariable.member

For example, if we want to access the roll member of the Student structure for s1, we write s1.roll.

Initializing a Structure

We can initialize a structure at the time of declaration:

struct Student {
   char name[50];
   int roll;
   float marks;
} s1 = {"John", 23, 85.5};

In this case, John, 23, and 85.5 are initial values of name, roll, and marks for s1, respectively.

Structures within Structures (Nested Structures)

We can also have structures within structures, known as nested structures. For example:

struct Address {
   char city[50];
   int pin;
};

struct Employee {
   char name[50];
   struct Address addr;
};

In the above example, Employee has two members: name and addr. The addr itself is a structure having two members: city and pin.

Understanding structures can take some time, but with consistent practice, you will get the hang of it. The structure is a powerful tool in C that allows more complex data models to be created, opening up a world of possibilities for more advanced programming. Keep practicing, and happy coding!

In the next tutorial, we'll look at Unions in C, which are similar to structures with a few key differences. Stay tuned!