Learn C++ (1) – Variables

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  • Post category:C++
  • Post last modified:2023-01-10

Reference

W3School – C++ Tutorial

C++ Variables

In C++, there are different types of variables (defined with different keywords), for example:

  • int – stores integers (whole numbers), without decimals, such as 123 or -123
  • double – stores floating point numbers, with decimals, such as 19.99 or -19.99
  • char – stores single characters, such as ‘a’ or ‘B’. Char values are surrounded by single quotes
  • string – stores text, such as “Hello World”. String values are surrounded by double quotes
  • bool – stores values with two states: true or false

Declaring (Creating) Variables

To create a variable, specify the type and assign it a value:

Syntax

type variableName = value;

Where type is one of C++ types (such as int), and variableName is the name of the variable (such as x or myName). The equal sign is used to assign values to the variable.

To create a variable that should store a number, look at the following example:

Example

int myNum = 15;
cout << myNum;

You can also declare a variable without assigning the value, and assign the value later.

Other Types

A demonstration of other data types:

int myNum = 5;               // Integer (whole number without decimals)
double myFloatNum = 5.99;    // Floating point number (with decimals)
char myLetter = 'D';         // Character
string myText = "Hello";     // String (text)
bool myBoolean = true;       // Boolean (true or false)

Display Variables

The cout object is used together with the << operator to display variables.

To combine both text and a variable, separate them with the << operator:

int myAge = 35;
cout << "I am " << myAge << " years old.";

Declare Many Variables

To declare more than one variable of the same type, use a comma-separated list:

int x = 5, y = 6, z = 50;
cout << x + y + z;

One Value to Multiple Variables

You can also assign the same value to multiple variables in one line:

int x, y, z;
x = y = z = 50;
cout << x + y + z;

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