C++ Variables
C++ Variables
Variables are containers for storing data values.
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 -123double- stores floating point numbers, with decimals, such as 19.99 or -19.99char- stores single characters, such as 'a' or 'B'. Char values are surrounded by single quotesstring- stores text, such as "Hello World". String values are surrounded by double quotesbool- 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
Create a variable called myNum of type int and assign it the value 15:
int myNum = 15;
cout << myNum;
Try it Yourself »
You can also declare a variable without assigning the value, and assign the value later:
Note that if you assign a new value to an existing variable, it will overwrite the previous value:
Example
int myNum = 15; // myNum is 15
myNum = 10; // Now myNum is 10
cout << myNum; // Outputs 10
Try it Yourself »
Other Types
A demonstration of other data types:
Example
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)
You will learn more about the individual types in the Data Types chapter.
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:
Add Variables Together
To add a variable to another variable, you can use the +
operator: