When we think of data in computers, we imagine various forms like text, images, videos, voice, 3D models, etc. Despite their different organizational forms, they are all composed of various fundamental data types.
When discussing data in computers, various forms like text, images, videos, voice and 3D models comes to mind. Despite their different organizational forms, they are all composed of various basic data types.
**Fundamental data types are those that the CPU can directly operate on** and are directly used in algorithms, mainly including the following.
**Basic data types are those that the CPU can directly operate on** and are directly used in algorithms, mainly including the following.
- Integer types: `byte`, `short`, `int`, `long`.
- Floating-point types: `float`, `double`, used to represent decimals.
- Character type: `char`, used to represent letters, punctuation, and even emojis in various languages.
- Boolean type: `bool`, used for "yes" or "no" decisions.
- Boolean type: `bool`, used to represent "yes" or "no" decisions.
**Fundamental data types are stored in computers in binary form**. One binary digit is equal to 1 bit. In most modern operating systems, 1 byte consists of 8 bits.
**Basic data types are stored in computers in binary form**. One binary digit is 1 bit. In most modern operating systems, 1 byte consists of 8 bits.
The range of values for fundamental data types depends on the size of the space they occupy. Below, we take Java as an example.
The range of values for basic data types depends on the size of the space they occupy. Below, we take Java as an example.
- The integer type `byte` occupies 1 byte = 8 bits and can represent $2^8$ numbers.
- The integer type `int` occupies 4 bytes = 32 bits and can represent $2^{32}$ numbers.
The following table lists the space occupied, value range, and default values of various fundamental data types in Java. This table does not need to be memorized, but understood roughly and referred to when needed.
The following table lists the space occupied, value range, and default values of various basic data types in Java. While memorizing this table isn't necessary, having a general understanding of it and referencing it when required is recommended.
<palign="center"> Table <id> Space Occupied and Value Range of Fundamental Data Types </p>
<palign="center"> Table <id> Space Occupied and Value Range of Basic Data Types </p>
| Type | Symbol | Space Occupied | Minimum Value | Maximum Value | Default Value |
Please note that the above table is specific to Java's fundamental data types. Each programming language has its own data type definitions, and their space occupied, value ranges, and default values may differ.
Please note that the above table is specific to Java's basic data types. Every programming language has its own data type definitions, which might differ in space occupied, value ranges, and default values.
- In Python, the integer type `int` can be of any size, limited only by available memory; the floating-point `float` is double precision 64-bit; there is no `char` type, as a single character is actually a string `str` of length 1.
- C and C++ do not specify the size of fundamental data types, which varies with implementation and platform. The above table follows the LP64 [data model](https://en.cppreference.com/w/cpp/language/types#Properties), used for Unix 64-bit operating systems including Linux and macOS.
- C and C++ do not specify the size of basic data types, it varies with implementation and platform. The above table follows the LP64 [data model](https://en.cppreference.com/w/cpp/language/types#Properties), used for Unix 64-bit operating systems including Linux and macOS.
- The size of `char` in C and C++ is 1 byte, while in most programming languages, it depends on the specific character encoding method, as detailed in the "Character Encoding" chapter.
- Even though representing a boolean only requires 1 bit (0 or 1), it is usually stored in memory as 1 byte. This is because modern computer CPUs typically use 1 byte as the smallest addressable memory unit.
So, what is the connection between fundamental data types and data structures? We know that data structures are ways to organize and store data in computers. The focus here is on "structure" rather than "data".
So, what is the connection between basic data types and data structures? We know that data structures are ways to organize and store data in computers. The focus here is on "structure" rather than "data".
If we want to represent "a row of numbers", we naturally think of using an array. This is because the linear structure of an array can represent the adjacency and order of numbers, but whether the stored content is an integer `int`, a decimal `float`, or a character `char`, is irrelevant to the "data structure".
If we want to represent "a row of numbers", we naturally think of using an array. This is because the linear structure of an array can represent the adjacency and the ordering of the numbers, but whether the stored content is an integer `int`, a decimal `float`, or a character `char`, is irrelevant to the "data structure".
In other words, **fundamental data types provide the "content type" of data, while data structures provide the "way of organizing" data**. For example, in the following code, we use the same data structure (array) to store and represent different fundamental data types, including `int`, `float`, `char`, `bool`, etc.
In other words, **basic data types provide the "content type" of data, while data structures provide the "way of organizing" data**. For example, in the following code, we use the same data structure (array) to store and represent different basic data types, including `int`, `float`, `char`, `bool`, etc.
=== "Python"
```python title=""
# Using various fundamental data types to initialize arrays
# Using various basic data types to initialize arrays
numbers: list[int] = [0] * 5
decimals: list[float] = [0.0] * 5
# Python's characters are actually strings of length 1
characters: list[str] = ['0'] * 5
bools: list[bool] = [False] * 5
# Python's lists can freely store various fundamental data types and object references
# Python's lists can freely store various basic data types and object references
data = [0, 0.0, 'a', False, ListNode(0)]
```
=== "C++"
```cpp title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
int numbers[5];
float decimals[5];
char characters[5];
@ -70,7 +70,7 @@ In other words, **fundamental data types provide the "content type" of data, whi
=== "Java"
```java title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
int[] numbers = new int[5];
float[] decimals = new float[5];
char[] characters = new char[5];
@ -80,7 +80,7 @@ In other words, **fundamental data types provide the "content type" of data, whi
=== "C#"
```csharp title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
int[] numbers = new int[5];
float[] decimals = new float[5];
char[] characters = new char[5];
@ -90,7 +90,7 @@ In other words, **fundamental data types provide the "content type" of data, whi
=== "Go"
```go title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
var numbers = [5]int{}
var decimals = [5]float64{}
var characters = [5]byte{}
@ -100,7 +100,7 @@ In other words, **fundamental data types provide the "content type" of data, whi
=== "Swift"
```swift title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
let numbers = Array(repeating: Int(), count: 5)
let decimals = Array(repeating: Double(), count: 5)
let characters = Array(repeating: Character("a"), count: 5)
@ -110,14 +110,14 @@ In other words, **fundamental data types provide the "content type" of data, whi
=== "JS"
```javascript title=""
// JavaScript's arrays can freely store various fundamental data types and objects
// JavaScript's arrays can freely store various basic data types and objects
const array = [0, 0.0, 'a', false];
```
=== "TS"
```typescript title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
const numbers: number[] = [];
const characters: string[] = [];
const bools: boolean[] = [];
@ -126,7 +126,7 @@ In other words, **fundamental data types provide the "content type" of data, whi
=== "Dart"
```dart title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
List<int> numbers = List.filled(5, 0);
List<double> decimals = List.filled(5, 0.0);
List<String> characters = List.filled(5, 'a');
@ -136,7 +136,7 @@ In other words, **fundamental data types provide the "content type" of data, whi
=== "Rust"
```rust title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
let numbers: Vec<i32> = vec![0; 5];
let decimals: Vec<f32> = vec![0.0, 5];
let characters: Vec<char> = vec!['0'; 5];
@ -146,7 +146,7 @@ In other words, **fundamental data types provide the "content type" of data, whi
=== "C"
```c title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
int numbers[10];
float decimals[10];
char characters[10];
@ -156,7 +156,7 @@ In other words, **fundamental data types provide the "content type" of data, whi
=== "Zig"
```zig title=""
// Using various fundamental data types to initialize arrays
// Using various basic data types to initialize arrays
Yuelin Xin
11 months ago
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