📌 Function Examples in C++

 

Functions in C++ allow code reusability by defining blocks of code that can be called multiple times. Here are some important function examples in C++:

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1️⃣ Hello World using Function

📌 A simple function to print "Hello World!"

#include <iostream>
using namespace std;

// Function definition
void sayHello() {
    cout << "Hello, World!" << endl;
}

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

🔹 Output

Hello, World!

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2️⃣ Call by Value & Reference in C++

📌 Call by Value: The function gets a copy of the argument.
📌 Call by Reference: The function gets the actual variable reference.

#include <iostream>
using namespace std;

// Call by Value
void callByValue(int x) {
    x = x + 10;
    cout << "Inside Call by Value: " << x << endl;
}

// Call by Reference
void callByReference(int &x) {
    x = x + 10;
    cout << "Inside Call by Reference: " << x << endl;
}

int main() {
    int num = 5;

    callByValue(num);
    cout << "After Call by Value: " << num << endl;

    callByReference(num);
    cout << "After Call by Reference: " << num << endl;

    return 0;
}

🔹 Output

Inside Call by Value: 15
After Call by Value: 5
Inside Call by Reference: 15
After Call by Reference: 15

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3️⃣ Function Overloading in C++

📌 Multiple functions with the same name but different parameters.

#include <iostream>
using namespace std;

// Function Overloading
void display(int x) {
    cout << "Integer: " << x << endl;
}
void display(double x) {
    cout << "Double: " << x << endl;
}
void display(string x) {
    cout << "String: " << x << endl;
}

int main() {
    display(10);
    display(3.14);
    display("Hello");

    return 0;
}

🔹 Output

Integer: 10
Double: 3.14
String: Hello

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4️⃣ Function Recursion Example in C++

📌 A function that calls itself to find the factorial of a number.

#include <iostream>
using namespace std;

int factorial(int n) {
    if (n == 0)
        return 1;
    else
        return n * factorial(n - 1);
}

int main() {
    int num = 5;
    cout << "Factorial of " << num << " is " << factorial(num) << endl;
    return 0;
}

🔹 Output

Factorial of 5 is 120

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5️⃣ Arithmetic Operations using Function

📌 Addition, Subtraction, Multiplication, and Division using functions.

#include <iostream>
using namespace std;

int add(int a, int b) { return a + b; }
int subtract(int a, int b) { return a - b; }
int multiply(int a, int b) { return a * b; }
double divide(double a, double b) { return a / b; }

int main() {
    int x = 10, y = 5;

    cout << "Addition: " << add(x, y) << endl;
    cout << "Subtraction: " << subtract(x, y) << endl;
    cout << "Multiplication: " << multiply(x, y) << endl;
    cout << "Division: " << divide(x, y) << endl;

    return 0;
}

🔹 Output

Addition: 15
Subtraction: 5
Multiplication: 50
Division: 2

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6️⃣ Check Prime Number using Function

📌 A function to check whether a number is prime or not.

#include <iostream>
using namespace std;

bool isPrime(int n) {
    if (n <= 1) return false;
    for (int i = 2; i * i <= n; i++) {
        if (n % i == 0) return false;
    }
    return true;
}

int main() {
    int num = 17;
    if (isPrime(num))
        cout << num << " is a Prime Number" << endl;
    else
        cout << num << " is not a Prime Number" << endl;

    return 0;
}

🔹 Output

17 is a Prime Number

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7️⃣ Tables using Function in C++

📌 Function to print multiplication tables.

#include <iostream>
using namespace std;

void printTable(int num) {
    for (int i = 1; i <= 10; i++) {
        cout << num << " x " << i << " = " << num * i << endl;
    }
}

int main() {
    int number = 5;
    printTable(number);
    return 0;
}

🔹 Output

5 x 1 = 5
5 x 2 = 10
...
5 x 10 = 50

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8️⃣ Display Marksheet using Function in C++

📌 Function to calculate total, percentage, and grade.

#include <iostream>
using namespace std;

void displayMarksheet(string name, int m1, int m2, int m3) {
    int total = m1 + m2 + m3;
    float percentage = total / 3.0;
    char grade;

    if (percentage >= 90) grade = 'A';
    else if (percentage >= 75) grade = 'B';
    else if (percentage >= 50) grade = 'C';
    else grade = 'F';

    cout << "Student: " << name << endl;
    cout << "Total Marks: " << total << endl;
    cout << "Percentage: " << percentage << "%" << endl;
    cout << "Grade: " << grade << endl;
}

int main() {
    displayMarksheet("Alice", 85, 78, 92);
    return 0;
}

🔹 Output

Student: Alice
Total Marks: 255
Percentage: 85%
Grade: B

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📌 Summary

✔ Functions increase code reusability.
✔ Call by Value vs. Call by Reference affects how values are passed.
✔ Function Overloading allows multiple functions with the same name.
✔ Recursion is useful for factorials and other iterative processes.
✔ Functions make complex programs modular and organized.

🚀 Need more examples? Let me know! 🔥