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Introduction to Functions in C

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Introduction

In C programming, functions are used to divide a program into smaller parts.
Instead of writing all code in one place, we can organize it into functions.

👉 Functions make programs:

• Easy to understand
• Easy to maintain
• Reusable

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What is a Function?

A function is a block of code that performs a specific task.

👉 It runs only when it is called.

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Why Use Functions?

• ✔ Avoid code repetition
• ✔ Improve readability
• ✔ Make debugging easier
• ✔ Reuse code multiple times

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Types of Functions

1. Library Functions (Predefined)
   👉 Example: printf(), scanf()
2. User-defined Functions
   👉 Created by the programmer

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Basic Structure of a Function

return_type function_name(parameters) {
    // function body
}

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Example of a Function

#include <stdio.h>

// Function definition
void display() {
    printf("Dharani Tech Edu Hub\n");
}

int main() {
    display();  // function call
    return 0;
}

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Output

Dharani Tech Edu Hub

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Function Components

1. Function Declaration (Prototype)
2. Function Definition
3. Function Call

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Example with All Components

#include <stdio.h>

// Declaration
void greet();

int main() {
    greet();  // Function call
    return 0;
}

// Definition
void greet() {
    printf("Welcome to TechEduHub\n");
}

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Flow of Function Execution

1. Program starts from main()
2. Function is called
3. Control goes to function
4. Executes function code
5. Returns to main

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Example: Function with Return Value

#include <stdio.h>

int add(int a, int b) {
    return a + b;
}

int main() {
    int result = add(5, 3);
    printf("Sum = %d", result);
    return 0;
}

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Output

Sum = 8

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Advantages of Functions

• ✔ Code reusability
• ✔ Modularity
• ✔ Easier debugging
• ✔ Better program structure

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Common Mistakes

• ❌ Forgetting function declaration
• ❌ Wrong return type
• ❌ Missing function call
• ❌ Incorrect parameters

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Pro Tips

• ✔ Use meaningful function names
• ✔ Keep functions small
• ✔ Avoid too many parameters
• ✔ Practice creating functions

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Conclusion

Functions are one of the most important concepts in C programming. They help you write clean, efficient, and organized code.

Mastering functions will make you a better programmer.

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👉 This article is part of Dharani Tech Edu Hub — where learning programming is made simple and practical.