1. "Hello, World!
" Program
#include <iostream>
using namespace std;
int main() {
cout << "Hello, World!" << endl;
return 0;
}
------------------------------------------------
2. Basic Input/Output Program
#include <iostream>
#include <string>
using namespace std;
int main() {
string name;
int age;
cout << "Enter your name: ";
getline(cin, name);
cout << "Enter your age: ";
cin >> age;
cout << "Hello, " << name << "! You are " <<
age << " years old." << endl;
return 0;
}
---------------------------------------------------
--------------
3. Simple Calculator Program
#include <iostream>
using namespace std;
int main() {
double num1, num2;
char operation;
cout << "Enter first number: ";
cin >> num1;
cout << "Enter second number: ";
cin >> num2;
cout << "Enter operation (+, -, *, /): ";
cin >> operation;
double result;
switch (operation) {
case '+':
result = num1 + num2;
break;
case '-':
result = num1 - num2;
break;
case '*':
result = num1 * num2;
break;
case '/':
if (num2 != 0) {
result = num1 / num2;
} else {
cout << "Error: Division by zero!"
<< endl;
return 1;
break;
default:
cout << "Error: Invalid operation!" <<
endl;
return 1;
cout << num1 << " " << operation << " " << num2
<< " = " << result << endl;
return 0;
}
---------------------------------------------------
----------------------
4. Temperature Conversion Program
#include <iostream>
using namespace std;
double celsiusToFahrenheit(double celsius) {
return (celsius * 9 / 5) + 32;
int main() {
double celsius;
cout << "Enter temperature in Celsius: ";
cin >> celsius;
double fahrenheit =
celsiusToFahrenheit(celsius);
cout << celsius << " degrees Celsius = " <<
fahrenheit << " degrees Fahrenheit" << endl;
return 0;
}
---------------------------------------------------
---------------
5. Factorial Calculation Program.
#include <iostream>
using namespace std;
int calculateFactorial(int n) {
if (n == 0 || n == 1) {
return 1;
} else {
return n * calculateFactorial(n - 1);
int main() {
int number;
cout << "Enter a non-negative integer: ";
cin >> number;
if (number < 0) {
cout << "Error: Factorial is not defined
for negative numbers!" << endl;
return 1;
int factorial = calculateFactorial(number);
cout << "Factorial of " << number << " is " <<
factorial << endl;
return 0;
}
---------------------------------------------------
---------------------
6. Palindrome Checker Program
#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
bool isPalindrome(string str) {
// Remove non-alphanumeric characters and
convert to lowercase
str.erase(remove_if(str.begin(), str.end(),
[](char c) { return !isalnum(c); }), str.end());
transform(str.begin(), str.end(), str.begin(),
::tolower);
// Check if the string is equal to its reverse
return equal(str.begin(), str.begin() +
str.size() / 2, str.rbegin());
int main() {
string str;
cout << "Enter a string: ";
getline(cin, str);
if (isPalindrome(str)) {
cout << "The string is a palindrome." <<
endl;
} else {
cout << "The string is not a palindrome."
<< endl;
return 0;
}
---------------------------------------------------
-------------------
7. Number Guessing Game
#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;
int main() {
srand(time(0)); // Seed the random number
generator
int secretNumber = rand() % 100 + 1; //
Generate a random number between 1 and 100
int guess;
int numGuesses = 0;
cout << "Welcome to the Number Guessing Game!"
<< endl;
cout << "I'm thinking of a number between 1 and
100." << endl;
do {
cout << "Enter your guess: ";
cin >> guess;
numGuesses++;
if (guess < secretNumber) {
cout << "Too low! Try again." << endl;
} else if (guess > secretNumber) {
cout << "Too high! Try again." << endl;
} else {
cout << "Congratulations! You guessed
the number in " << numGuesses << " guesses!" <<
endl;
}
} while (guess != secretNumber);
return 0;
}
---------------------------------------------------
--------------------
8. Basic File I/O Program
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main() {
string filename = "example.txt";
string data;
// Writing to a file
ofstream outputFile(filename);
if (outputFile.is_open()) {
cout << "Enter data to write to the file
(press Enter without input to finish):" << endl;
while (getline(cin, data) && !data.empty())
{
outputFile << data << endl;
outputFile.close();
cout << "Data written to the file
successfully." << endl;
} else {
cout << "Unable to open the file for
writing." << endl;
// Reading from a file
ifstream inputFile(filename);
if (inputFile.is_open()) {
cout << "Contents of the file:" << endl;
while (getline(inputFile, data)) {
cout << data << endl;
inputFile.close();
} else {
cout << "Unable to open the file for
reading." << endl;
return 0;
}
---------------------------------------------------
-----------------
9. Array Manipulation Program
#include <iostream>
using namespace std;
const int SIZE = 5;
void printArray(const int arr[], int size) {
for (int i = 0; i < size; i++) {
cout << arr[i] << " ";
cout << endl;
int main() {
int numbers[SIZE];
// Initialize the array with user input
cout << "Enter " << SIZE << " integers:" <<
endl;
for (int i = 0; i < SIZE; i++) {
cin >> numbers[i];
cout << "Original array: ";
printArray(numbers, SIZE);
// Multiply each element by 2
for (int i = 0; i < SIZE; i++) {
numbers[i] *= 2;
cout << "Array after multiplying each element
by 2: ";
printArray(numbers, SIZE);
// Find the sum and average of the elements
int sum = 0;
for (int i = 0; i < SIZE; i++) {
sum += numbers[i];
double average = static_cast<double>(sum) /
SIZE;
cout << "Sum of the elements: " << sum << endl;
cout << "Average of the elements: " << average
<< endl;
return 0;
}
---------------------------------------------------
---------------------
10. Errors in C++
#include <iostream>
using namespace std;
int main() {
int x = 10;
cout << x / 0; // Runtime error: division by
zero
return 0;
}
11. Forward Declarations in C++
#include <iostream>
using namespace std;
void displayMessage(); // Forward declaration
int main() {
displayMessage();
return 0;
}
void displayMessage() { // Function definition
cout << "Hello, world!" << endl;
}
12. Storage Classes in C++
#include <iostream>
using namespace std;
void counterFunction() {
static int count = 0; // Static variable
retains its value
count++;
cout << "Count: " << count << endl;
}
int main() {
counterFunction();
counterFunction();
counterFunction();
return 0;
}
