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;
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 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;
C++ supports different types of arithmetic operators that can perform common mathematical operations:
%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
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
int tip = 0; std::cout << "Enter amount: "; std::cin >> tip;
Chaining the Output
std::cout can output multiple values by chaining them using the output operator
Here, the output would be
int age = 28; std::cout << "I'm " << age << ".\n";
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 = '?';
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 is a type for storing
false boolean values. Booleans typically require 1 byte of memory space.
bool organ_donor = true; bool late_to_work = false;