C++ Data Types
- C++ provides built-in data types that correspond to integers, characters, floating-point values, and Boolean values.
- These are the ways that data is commonly stored and manipulated by a program.
- C++ allows you to construct more sophisticated types, such as classes, structures, and enumerations, but these too are ultimately composed of the built-in types.
At the core of the C++ type system are the seven basic data types shown here:
Type |
Meaning |
char |
Character |
wchar_t |
Wide character |
int |
Integer |
float |
Floating point |
double |
Double floating point |
bool |
Boolean |
void |
Valueless |
C++ allows certain of the basic types to have modifiers preceding them. A modifier alters the meaning of the base type so that it more precisely fits the needs of various situations. The data type modifiers are listed here:
- signed
- unsigned
- long
- short
Integers
Variables are the most fundamental part of any language. A variable has a symbolic name and can be given a variety of values. Variables are located in particular places in the computer’s memory.
int var1;
int var2;
Characters
Variables of type char hold 8-bit ASCII characters such as A, z, or G, or any other 8-bit quantity. To specify a character, you must enclose it between single quotes.
Thus, this assigns X to the variable ch:
char ch;
ch = 'X';
cout << "This is ch: " << ch;
Output
This is ch: X
Floating-Point Types
- Floating-point variables represent numbers with a decimal place—like 3.1415927, 0.0000625, and –10.2.
- They have both an integer part, to the left of the decimal point, and a fractional part, to the right.
- Floating-point variables represent what mathematicians call real numbers, which are used for measurable quantities such as distance, area, and temperature. They typically have a fractional part.
The bool Type
- The bool type is a relatively recent addition to C++. It stores Boolean (that is, true/false) values.
- C++ defines two Boolean constants, true and false, which are the only two values that a bool value can have. Before continuing, it is important to understand how true and false are defined by C++.
- One of the fundamental concepts in C++ is that any nonzero value is interpreted as true and zero is false.
void
- The void type specifies a valueless expression.