Cheatsheets
Learn C++ Basics

Learn C++ Basics

Getting Started

How to compile your code

To compile your C++ code using GNU, you use the `g++` command followed by the name of your source file. For instance, if your file is named `hello.cpp`, you would use `g++ hello.cpp`.

                                
g++ hello.cpp

How to run Your program

After compiling, you can run your program using `./` followed by the name of the executable file. By default, the executable is named `a.out`.

                                
./a.out

Writing single-line comments

Single-line comments start with `//`. Everything after `//` on that line is ignored by the compiler.

                                
// This is a single-line comment

Writing multi-line comments

Multi-line comments start with `/*` and end with `*/`. Everything between these markers is ignored by the compiler.

                                
/* 
This is a multi-line comment.
It spans multiple lines.
*/

Basic program structure

A basic C++ program runs from top to bottom. Here’s a simple example:

                                
#include <iostream>
int main() {
  std::cout << "1\n";
  std::cout << "2\n";
  std::cout << "3\n";
  return 0;
}</iostream>

Printing text to the screen

Use `std::cout` to print text to the screen. You use the `<<` operator to send the text to `std::cout`.

                                
std::cout << "Hello World!\n";

Adding new lines

Use `\n` to add a new line in your output. It moves the cursor to the next line.

                                
std::cout << "Hello\n";
std::cout << "World\n";

Working with Variables

Getting user input

Use `std::cin` to get input from the user. The `>>` operator reads the input and stores it in a variable.

                                
int amount = 0;
std::cout << "Enter amount: ";
std::cin >> amount;

Understanding Variables

Variables store data. You declare a variable and then assign a value to it. For example, `int score = 0;` creates a variable `score` and sets it to 0.

                                
int score;
score = 0;

Using arithmetic operators

Arithmetic operators perform math operations. For example, `+` adds, `-` subtracts, `*` multiplies, `/` divides, and `%` gives the remainder.

                                
int x = 4 + 2;  // x is now 6
x = 4 - 2;  // x is now 2
x = 4 * 2;  // x is now 8
x = 4 / 2;  // x is now 2
x = 4 % 2;  // x is now 0

Using floating-point numbers

Use `double` for decimal numbers. For example, `double price = 8.99;` stores a decimal number.

                                
double price = 8.99;
double pi = 3.14159;

Chaining output statements

You can output multiple values in a single statement by chaining them with `<<`.

                                
int age = 28;
std::cout << "I'm " << age << ".\n";

Using integer variables

Use `int` for whole numbers. For example, `int year = 1991;` stores an integer value.

                                
int year = 1991;
int age = 28;

Storing characters

Use `char` to store a single character. Characters are enclosed in single quotes, like `'A'`.

                                
char grade = 'A';
char punctuation = '?';

Using Strings

Use `std::string` to store a sequence of characters (text). For example, `std::string name = "Alice";` stores a name.

                                
std::string message = "Good night";
std::string user = "Codey";

Using Boolean Values

Use `bool` to store `true` or `false` values. For example, `bool isValid = true;`.

                                
bool isStudent = true;
bool hasPaid = false;

Making decisions

Using an if Statement

An `if` statement checks if a condition is true. If it is, the code inside the `if` block runs.

                                
if (a == 10) {
  // This code runs if a is 10
}

Using an else Clause

An `else` clause provides an alternative block of code that runs if the `if` condition is false.

                                
if (year == 1991) {
  // Code runs if year is 1991
}
else {
  // Code runs if year is not 1991
}

Comparing Values with Relational Operators

Relational operators compare values and return true or false. For example, `a > 10` checks if `a` is greater than 10.

                                
if (a > 10) {
  // Code runs if a is greater than 10
}

Using else if for Multiple Conditions

An `else if` statement allows you to check multiple conditions. If the first condition is false, it checks the next one.

                                
if (apple > 8) {
  // Code runs if apple is more than 8
}
else if (apple > 6) {
  // Code runs if apple is more than 6 but not more than 8
}
else {
  // Code runs if apple is 6 or less
}

Using a switch Statement

A `switch` statement allows you to choose between multiple options based on the value of a variable.

                                
switch (grade) {
  case 9:
    std::cout << "Freshman\n";
    break;
  case 10:
    std::cout << "Sophomore\n";
    break;
  case 11:
    std::cout << "Junior\n";
    break;
  case 12:
    std::cout << "Senior\n";
    break;
  default:
    std::cout << "Invalid\n";
    break;
}

Combining Conditions with Logical Operators

Logical operators combine multiple conditions. `&&` means 'and', `||` means 'or', and `!` means 'not'.

                                
if (coffee > 0 && donut > 1) {
  // Runs if both conditions are true
}
if (coffee > 0 || donut > 1) {
  // Runs if either condition is true
}
if (!tired) {
  // Runs if tired is false
}

Programming Cheatsheets: Quick Reference for Productivity

Welcome to our comprehensive collection of programming language cheatsheets! Whether you're a seasoned developer or a beginner, these quick reference guides provide essential tips and key information for all major languages. They focus on core concepts, commands, and functions—designed to enhance your efficiency and productivity.

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Online Training
Q4 2024

Learn C++ Basics

Topics

Getting Started

How to compile your code

How to run Your program

Writing single-line comments

Writing multi-line comments

Basic program structure

Printing text to the screen

Adding new lines

Working with Variables

Getting user input

Understanding Variables

Using arithmetic operators

Using floating-point numbers

Chaining output statements

Using integer variables

Storing characters

Using Strings

Using Boolean Values

Making decisions

Using an if Statement

Using an else Clause

Comparing Values with Relational Operators

Using else if for Multiple Conditions

Using a switch Statement

Combining Conditions with Logical Operators

Programming Cheatsheets: Quick Reference for Productivity

Recent Releases

Blogs

Learn

Tools

Online Training Q4 2024

Learn C++ Basics

Topics

Getting Started

How to compile your code

How to run Your program

Writing single-line comments

Writing multi-line comments

Basic program structure

Printing text to the screen

Adding new lines

Working with Variables

Getting user input

Understanding Variables

Using arithmetic operators

Using floating-point numbers

Chaining output statements

Using integer variables

Storing characters

Using Strings

Using Boolean Values

Making decisions

Using an if Statement

Using an else Clause

Comparing Values with Relational Operators

Using else if for Multiple Conditions

Using a switch Statement

Combining Conditions with Logical Operators

Programming Cheatsheets: Quick Reference for Productivity

Recent Releases

Blogs

Learn

Tools

Online Training
Q4 2024