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++:
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!
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
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
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
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
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
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
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
📌 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! 🔥
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