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Learn C++ — 10 Examples
with Console Output

Each example below teaches one C++ concept. Read the code, press Run — See Output, and the console output appears instantly. Copy any example with the copy button.

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Hello, World!

Every programmer starts here. This program prints a message to the screen. It uses cout — which stands for "console output" — to display text.

📚 Teaches: Basic program structure, #include, main function, cout

example1.cppC++

1#include 
2using namespace std;
3 
4int main() {
5    cout << "Hello, World!" << endl;
6    return 0;
7}

Variables and Data Types

Variables are containers that store values. C++ requires you to declare the type of each variable before using it — int for whole numbers, double for decimals, string for text.

📚 Teaches: int, double, string, variable declaration, cout

example2.cppC++

1#include 
2#include 
3using namespace std;
4 
5int main() {
6    int age = 20;
7    double price = 9.99;
8    string name = "Alice";
9 
10    cout << "Name: " << name << endl;
11    cout << "Age: " << age << endl;
12    cout << "Price: $" << price << endl;
13 
14    return 0;
15}

Getting User Input

cin reads input from the user (keyboard). The >> operator sends the input into your variable. This is the opposite of cout <<.

📚 Teaches: cin, >> operator, reading input, storing in variables

example3.cppC++

1#include 
2#include 
3using namespace std;
4 
5int main() {
6    string name;
7    int age;
8 
9    cout << "Enter your name: ";
10    cin >> name;
11 
12    cout << "Enter your age: ";
13    cin >> age;
14 
15    cout << "Hello, " << name << "!" << endl;
16    cout << "You are " << age << " years old." << endl;
17 
18    return 0;
19}

If / Else Conditions

Conditions let your program make decisions. If a condition is true, one block of code runs. If it is false, another block runs instead.

📚 Teaches: if, else if, else, comparison operators, conditions

example4.cppC++

1#include 
2using namespace std;
3 
4int main() {
5    int score = 75;
6 
7    if (score >= 90) {
8        cout << "Grade: A" << endl;
9    } else if (score >= 75) {
10        cout << "Grade: B" << endl;
11    } else if (score >= 60) {
12        cout << "Grade: C" << endl;
13    } else {
14        cout << "Grade: F" << endl;
15    }
16 
17    return 0;
18}

For Loop

A for loop repeats a block of code a set number of times. You set a starting value, a condition to keep looping, and how to update the counter each time.

📚 Teaches: for loop, counter variable, loop body, iteration

example5.cppC++

1#include 
2using namespace std;
3 
4int main() {
5    // Print numbers 1 to 5
6    for (int i = 1; i <= 5; i++) {
7        cout << "Count: " << i << endl;
8    }
9 
10    cout << "Done!" << endl;
11    return 0;
12}

While Loop

A while loop keeps running as long as a condition is true. It is useful when you do not know in advance how many times to repeat.

📚 Teaches: while loop, condition, infinite loop prevention

example6.cppC++

1#include 
2using namespace std;
3 
4int main() {
5    int number = 1;
6 
7    while (number <= 5) {
8        cout << number << " x 2 = " << number * 2 << endl;
9        number++;  // increase by 1 each time
10    }
11 
12    return 0;
13}

Functions

A function is a reusable block of code that does one specific job. You define it once and call it as many times as you need. Functions make your code organised and avoid repetition.

📚 Teaches: function definition, parameters, return type, calling functions

example7.cppC++

1#include 
2using namespace std;
3 
4// Function that adds two numbers
5int add(int a, int b) {
6    return a + b;
7}
8 
9// Function that greets a person
10void greet(string name) {
11    cout << "Hello, " << name << "!" << endl;
12}
13 
14int main() {
15    int result = add(10, 5);
16    cout << "10 + 5 = " << result << endl;
17 
18    greet("Bob");
19    greet("Alice");
20 
21    return 0;
22}

Arrays

An array stores multiple values of the same type in one variable. You access each value using its index number, starting from 0.

📚 Teaches: array declaration, indexing from 0, array size, looping through arrays

example8.cppC++

1#include 
2using namespace std;
3 
4int main() {
5    // Array of 5 scores
6    int scores[5] = {88, 92, 75, 96, 81};
7 
8    cout << "All scores:" << endl;
9    for (int i = 0; i < 5; i++) {
10        cout << "Score " << i + 1 << ": " << scores[i] << endl;
11    }
12 
13    return 0;
14}

Classes and Objects

A class is like a blueprint. An object is something built from that blueprint. Classes bundle together related data (attributes) and actions (methods) into one package — this is the core idea of Object-Oriented Programming.

📚 Teaches: class, object, attributes, methods, constructor, OOP basics

example9.cppC++

1#include 
2#include 
3using namespace std;
4 
5class Dog {
6public:
7    string name;
8    string breed;
9    int age;
10 
11    // Method — an action the Dog can do
12    void bark() {
13        cout << name << " says: Woof!" << endl;
14    }
15 
16    void info() {
17        cout << name << " is a " << breed;
18        cout << " aged " << age << endl;
19    }
20};
21 
22int main() {
23    Dog myDog;          // create an object
24    myDog.name  = "Rex";
25    myDog.breed = "Labrador";
26    myDog.age   = 3;
27 
28    myDog.info();
29    myDog.bark();
30 
31    return 0;
32}

Simple Calculator

Putting it all together — this program uses variables, conditions and functions to build a working calculator. It shows how the concepts from all previous examples combine into a real program.

📚 Teaches: switch statement, combining concepts, real program structure

example10.cppC++

1#include 
2using namespace std;
3 
4double calculate(double a, char op, double b) {
5    if (op == '+') return a + b;
6    if (op == '-') return a - b;
7    if (op == '*') return a * b;
8    if (op == '/') return a / b;
9    return 0;
10}
11 
12int main() {
13    double num1 = 20;
14    double num2 = 4;
15 
16    cout << num1 << " + " << num2 << " = ";
17    cout << calculate(num1, '+', num2) << endl;
18 
19    cout << num1 << " - " << num2 << " = ";
20    cout << calculate(num1, '-', num2) << endl;
21 
22    cout << num1 << " * " << num2 << " = ";
23    cout << calculate(num1, '*', num2) << endl;
24 
25    cout << num1 << " / " << num2 << " = ";
26    cout << calculate(num1, '/', num2) << endl;
27 
28    return 0;
29}

Quick Reference

C++ Cheat Sheet

The most important C++ syntax at a glance. Bookmark this section.

SyntaxWhat it does

#include <iostream>Include the input/output library

using namespace std;Use the standard namespace (saves typing std::)

int main() { }Main function — every program starts here

cout << "text"Print text to the console

cin >> variableRead input from the keyboard

endlEnd the line (like pressing Enter)

int x = 5;Declare an integer variable

double x = 3.14;Declare a decimal number variable

string s = "hello";Declare a text variable

if (x > 0) { }Run code only if condition is true

for (int i=0; i<n; i++)Loop n times

while (condition) { }Loop while condition is true

int fn(int a) { }Define a function that returns int

return 0;Exit main — 0 means success

class Name { };Define a class (object blueprint)

// commentSingle-line comment (ignored by compiler)

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Learn C++ — 10 Exampleswith Console Output