C Tutorial

💻 Functions in C

A function in C is a block of code that performs a specific task. Functions allow us to break down a program into smaller, reusable components, improving code readability and maintainability.

🔄 Syntax of a Function

The general syntax of a function in C is:

return_type function_name(parameters) {
    // Function body
    return value; // optional depending on return type
}
  

- return_type: Specifies the type of value the function returns (e.g., int, float, void). - function_name: The name of the function. - parameters: Inputs to the function, which can be variables or constants.

🔧 Example: Simple Function

#include 

// Function declaration
void greet() {
    printf("Hello, World!\n");
}

int main() {
    greet(); // Calling the function
    return 0;
}
  

📌 Function with Parameters

Functions can also accept parameters to process specific values. Here's an example:

#include 

// Function declaration
void add(int a, int b) {
    printf("Sum: %d\n", a + b);
}

int main() {
    int x = 5, y = 3;
    add(x, y); // Calling the function with arguments
    return 0;
}
  

🔧 Function with Return Value

A function can also return a value. Here's an example:

#include 

// Function declaration
int multiply(int a, int b) {
    return a * b; // Returns the product
}

int main() {
    int result = multiply(4, 5); // Calling the function and storing the result
    printf("Product: %d\n", result);
    return 0;
}
  

🔧 Function Declaration vs Definition

A declaration informs the compiler about the function's signature, while a definition provides the actual body of the function. Here's an example:

#include 

// Function declaration
void hello();

// Function definition
void hello() {
    printf("Hello, World!\n");
}

int main() {
    hello(); // Calling the function
    return 0;
}
  

💡 Key Points to Remember

• A function allows code reuse and modular programming.
• Functions can have parameters and return values for processing data.
• Function declaration is used to inform the compiler about the function's prototype, while function definition provides the implementation.
• Functions can be called inside other functions, and this is useful in breaking a problem into smaller tasks.

📝 Try It Yourself!

❌ Common Mistakes

• 🚫 Forgetting to return a value from a function that is supposed to return something (e.g., int or float).
• 🚫 Mismatching the return type of the function with the actual return value (e.g., returning a string from an int function).
• 🚫 Calling a function before declaring or defining it in the program.

🌟 More Interactive Exercises

Create a program with multiple functions performing different operations, and call them from the main function based on user input. Try to use at least 4 different functions in your program!