C Structures

1. What is a C Structures?

A C Structures is a user-defined data type in C.
It allows you to store multiple variables of different data types under a single name.
Useful for representing complex objects like a student, employee, or point in 2D space.

Syntax:

2. Example: Defining a Structure

#include <stdio.h>

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

int main() {
struct Student s1;

s1.id = 101;
strcpy(s1.name, "Alice"); // string copy
s1.marks = 95.5;

printf("ID: %d\n", s1.id);
printf("Name: %s\n", s1.name);
printf("Marks: %.2f\n", s1.marks);

return 0;
}

#include <stdio.h>

struct Student {

int id;

char name[50];

float marks;

};

int main() {

struct Student s1;

s1.id = 101;

strcpy(s1.name, "Alice"); // string copy

s1.marks = 95.5;

printf("ID: %d\n", s1.id);

printf("Name: %s\n", s1.name);

printf("Marks: %.2f\n", s1.marks);

return 0;

}

Output:

Use strcpy() from <string.h> to assign string values to char arrays.

3. Declaring Structure Variables

You can also declare and define together using typedef (simpler):

4. Accessing Structure Members

Use the dot . operator for normal variables:

For pointers to structures, use arrow -> operator:

5. Example: Structure Pointer

Output:

6. Nested Structures

Structures can contain other structures:

#include <stdio.h>

struct Date {
int day, month, year;
};

struct Student {
char name[50];
struct Date dob; // nested structure
};

int main() {
struct Student s1;
strcpy(s1.name, "Alice");
s1.dob.day = 15;
s1.dob.month = 8;
s1.dob.year = 2005;

printf("Name: %s\n", s1.name);
printf("DOB: %d-%d-%d\n", s1.dob.day, s1.dob.month, s1.dob.year);

return 0;
}

#include <stdio.h>

struct Date {

int day, month, year;

};

struct Student {

char name[50];

struct Date dob; // nested structure

};

int main() {

struct Student s1;

strcpy(s1.name, "Alice");

s1.dob.day = 15;

s1.dob.month = 8;

s1.dob.year = 2005;

printf("Name: %s\n", s1.name);

printf("DOB: %d-%d-%d\n", s1.dob.day, s1.dob.month, s1.dob.year);

return 0;

}

Output:

7. Array of Structures

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

int main() {
struct Student students[2];

students[0].id = 101;
strcpy(students[0].name, "Alice");
students[0].marks = 95.5;

students[1].id = 102;
strcpy(students[1].name, "Bob");
students[1].marks = 89.0;

for(int i=0; i<2; i++) {
printf("ID: %d, Name: %s, Marks: %.2f\n",
students[i].id, students[i].name, students[i].marks);
}

return 0;
}

struct Student {

int id;

char name[50];

float marks;

};

int main() {

struct Student students[2];

students[0].id = 101;

strcpy(students[0].name, "Alice");

students[0].marks = 95.5;

students[1].id = 102;

strcpy(students[1].name, "Bob");

students[1].marks = 89.0;

for(int i=0; i<2; i++) {

printf("ID: %d, Name: %s, Marks: %.2f\n",

students[i].id, students[i].name, students[i].marks);

}

return 0;

}

Output:

8. Key Points About C Structures

Structures group different data types into a single entity.
Access members using dot . (normal) or arrow -> (pointer).
Use typedef to simplify structure names.
Can have nested structures and arrays of structures.
Structures are commonly used in records, objects, and complex data handling.

C Structures

1. What is a C Structures?

2. Example: Defining a Structure

3. Declaring Structure Variables

4. Accessing Structure Members

5. Example: Structure Pointer

6. Nested Structures

7. Array of Structures

8. Key Points About C Structures

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