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Variables

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User Input

std::cin, which stands for “character input”, reads user input from the keyboard.

Here, the user can enter a number, press enter, and that number will get stored in tip.

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

Variables

A variable refers to a storage location in the computer’s memory that one can set aside to save, retrieve, and manipulate data.

// Declare a variable int score; // Initialize a variable score = 0;

Arithmetic Operators

C++ supports different types of arithmetic operators that can perform common mathematical operations:

  • + addition
  • - subtraction
  • * multiplication
  • / division
  • % modulo (yields the remainder)
int x = 0; 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

int Type

int is a type for storing integer (whole) numbers. An integer typically requires 4 bytes of memory space and ranges from -2³¹ to 2³¹.

int year = 1991; int age = 28;

double Type

double is a type for storing floating point (decimal) numbers. Double variables typically require 8 bytes of memory space.

double price = 8.99; double pi = 3.14159;

Chaining the Output

std::cout can output multiple values by chaining them using the output operator <<.

Here, the output would be I'm 28.

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

char Type

char is a type for storing individual characters. Characters are wrapped in single quotes '. Characters typically require 1 byte of memory space and range from -128 to 127.

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

string Type

std::string is a type for storing text strings. Strings are wrapped in double quotes ".

std::string message = "good nite"; std::string user = "@sonnynomnom";

bool Type

bool is a type for storing true or false boolean values. Booleans typically require 1 byte of memory space.

bool organ_donor = true; bool late_to_work = false;