Basic Data Types:

C++ provides a rather large number of types. However, you can write perfectly good programs using only five of those:

Basic C++ Data Types

Here are some examples of declaring and intializing variables:

int age = 33; double price = 1.25; char grade = 'A'; std::string game_output = "Game Over"; bool is_registered_to_vote = true;

Datatype Modifiers:

As the name implies, datatype modifiers are used with the built-in data types to modify the length of data that a particular data type can hold. Data type modifiers in C++ are:

  • signed
  • unsigned
  • short
  • long

We will learn about these in a bit!


const (constant) variables cannot be changed by your program during execution.

const double quarter = 0.25; // and now variable quarter can only be 0.25

Simply add the keyword const before the data type during declaration to make the variable not modifiable. It is also common to see const variable names in all uppercase like QUARTER.

Type Conversion:

A type cast is basically a conversion from one type to another.

The notation (type) value means “convert value to type“. So for example:

double weight1; int weight2; weight1 = 154.49; weight2 = (int) weight1; // weight2 is now 154

Note: Going from a double to an int simply removes the decimal. There’s no rounding involved.