Introduction to Programming in C

📘 Enumerations and Typedef in C

Enumerations and typedef are powerful features in C used to improve code readability and maintainability. Enumerations let you assign names to integral constants, while typedef simplifies complex data type definitions.

🔹 What is Enumeration (enum)?

Enumeration is a user-defined data type consisting of named integer constants. It enhances clarity in code that uses a set of fixed values.

enum Day { SUN, MON, TUE, WED, THU, FRI, SAT };

int main() {
    enum Day today = WED;
    printf("Day number: %d\n", today); // Output: 3
    return 0;
}

💡 Note:

• By default, values start from 0 and increment by 1.
• You can explicitly assign custom values too.

enum Status { PENDING = 1, ACTIVE = 5, SUSPENDED = 10 };

📚 UdaanPath Example: Course Status

enum CourseStatus { UPCOMING, LIVE, COMPLETED };

int main() {
    enum CourseStatus status = LIVE;
    if (status == LIVE) {
        printf("Your UdaanPath course is currently live!\n");
    }
    return 0;
}

🔹 What is typedef?

typedef is used to create a new name (alias) for an existing data type. This is helpful in simplifying code that involves pointers or structures.

typedef unsigned int u_int;

u_int a = 10, b = 20;
printf("%u", a + b);

👨‍💻 With Structures:

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

Student s1 = {101, "Ravi"};

📌 Combining typedef and struct

This technique is frequently used in real-world applications like databases, compilers, and embedded systems.

typedef struct {
    char courseName[100];
    int duration;
} Course;

Course c1 = {"C Programming - UdaanPath", 40};

📝 Practice Questions

1. Create an enum for the days of the week and print them.
2. Define a typedef for float and use it to store average marks.
3. Use typedef with a struct for book details (title, price).
4. Write a program to accept and display student details using typedef.

✅ Summary

• enum is ideal for grouping related constants.
• typedef helps shorten complex data types.
• Combining enum and typedef improves code clarity and maintainability.

🚀 Coming Next

In the next chapter, we’ll learn File Handling in C — how to read, write, and manage files using functions like fopen, fscanf, and fprintf.