C++ Beginner Tutorial — Single Session (Up to Arrays)

This file is designed to teach basic C++ concepts to beginners. It contains detailed explanations and simple examples so you can cover all foundational topics in one session. Functions, arrays, strings, and vectors are excluded in this version.

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🎯 Learning Objectives

• Understand the general structure of a C++ program and how it executes.
• Learn to define variables and basic data types.
• Understand operators, especially increment and decrement operators.
• Get familiar with conditionals (if, else, switch) and loops (for, while, do-while).

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🧩 1) Introduction and Basic Structure

C++ is a powerful and widely used programming language in fields like engineering, simulation, and game development. Every C++ program starts from the main() function and usually contains statements for input and output.

#include <iostream>
using namespace std;

int main() {
    cout << "Hello World!" << endl;
    return 0;
}

Explanation:

• #include <iostream> allows using input and output commands.
• using namespace std; removes the need to write std:: before cout or cin.
• main() is the starting point of the program.
• return 0; indicates successful execution.

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💬 2) Input and Output

In C++, cout is used for output, and cin for input.

#include <iostream>
using namespace std;

int main() {
    string name;
    int age;
    cout << "Enter your name: ";
    cin >> name;
    cout << "Enter your age: ";
    cin >> age;
    cout << "Hello " << name << ", you are " << age << " years old." << endl;
    return 0;
}

Note: cout stands for console output and cin stands for console input.

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🧠 3) Data Types and Variable Declaration

In C++, variables store data and must have a specific data type.

Data Type	Description	Example
int	Integer	int x = 10;
double	Decimal number	double pi = 3.14;
char	Single character	char grade = 'A';
bool	True or false	bool isOk = true;
string	Text (word or sentence)	string name = "Ali";

Important Notes:

• Variable names cannot start with a number.
• Case-sensitive (Age and age are different).
• Multiple variables of the same type can be declared together:

  int a = 10, b = 20, c = 30;

Example:

int number = 5;
double price = 12.5;
char letter = 'C';
bool passed = false;

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➕ 4) Operators

a) Arithmetic Operators

Operator	Meaning	Example
+	Addition	x + y
-	Subtraction	x - y
*	Multiplication	x * y
/	Division	x / y
%	Modulus	x % y

b) Comparison Operators

Operator	Meaning	Example
==	Equal to	x == y
!=	Not equal	x != y
>	Greater than	x > y
<	Less than	x < y
>=	Greater or equal	x >= y
<=	Less or equal	x <= y

c) Logical Operators

Operator	Meaning	Example
&&	AND	(x > 0 && y > 0)
||	OR	(x > 0 || y > 0)
!	NOT	!(x > 0)

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🔁 5) Increment and Decrement Operators (++ and --)

These operators are used to increase or decrease a variable.

int i = 5;
i++; // i = 6
++i; // i = 7

Prefix (++i) vs. Postfix (i++):

• ++i: increases first, then uses the value.
• i++: uses the value first, then increases.

Example:

int a = 5;
cout << a++ << endl; // prints 5, then a becomes 6
cout << ++a << endl; // a becomes 7, then prints 7

Similarly:

int b = 5;
b--; // b = 4
--b; // b = 3

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⚙️ 6) Conditionals (if / else / switch)

Conditionals are used to make decisions in programs.

int number;
cout << "Enter a number: ";
cin >> number;

if (number > 0) {
    cout << "Positive number" << endl;
} else if (number < 0) {
    cout << "Negative number" << endl;
} else {
    cout << "Zero" << endl;
}

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🔄 7) Loops

Loops execute a block of code multiple times. C++ has three main loop types:

🔹 for loop

Used when the number of iterations is known.

for (int i = 1; i <= 5; i++) {
    cout << i << " ";
}

🔹 while loop

Used when the number of iterations is unknown and the loop continues as long as a condition is true.

int i = 1;
while (i <= 5) {
    cout << i << " ";
    i++;
}

🔹 do-while loop

Similar to while, but executes at least once even if the condition is false.

int i = 1;
do {
    cout << i << " ";
    i++;
} while (i <= 5);

🔹 break and continue

• break: exits the loop immediately.
• continue: skips to the next iteration without executing the remaining statements in the loop.

Example:

for (int i = 1; i <= 5; i++) {
    if (i == 3) continue; // skip printing 3
    if (i == 5) break;    // exit loop when i is 5
    cout << i << " ";
}
// output: 1 2 4

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🧭 8) switch-case Statement

Used when you want to check multiple possible values of a variable (instead of multiple if-else).

int day = 3;
switch (day) {
    case 1:
        cout << "Saturday";
        break;
    case 2:
        cout << "Sunday";
        break;
    case 3:
        cout << "Monday";
        break;
    case 4:
        cout << "Tuesday";
        break;
    case 5:
        cout << "Wednesday";
        break;
    default:
        cout << "Invalid day";
}

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📚 Useful Resources

• W3Schools C++ Tutorial
• cppreference.com for