Differences and Usage Analysis of Golang Constants and Variables

To master the difference and usage of constants and variables in Golang, you need specific code examples

In Golang, constants and variables are the most basic components of the program. There are some differences in storage and assignment methods. This article will introduce in detail the difference and usage of constants and variables in Golang, and provide specific code examples to help readers better understand and master these two concepts.

1. Constants

Constants are quantities that do not change during the running of the program. In Golang, constants are declared using the keyword const. Once a constant is assigned a value, it is not allowed to be modified again while the program is running. A constant can be declared anywhere in the program, but its value must be determined at compile time.

The naming convention of constants is the same as that of variables, starting with a letter or underscore, and can contain letters, numbers, and underscores. Constants can be data types such as characters, strings, Boolean values, and numeric values. The following is some sample code for constants:

const PI = 3.14159
const Name = "Alice"
const Age = 18
const IsMale = true

In the above code, PI is a floating point constant, Name is a string constant, Age is an integer constant, and IsMale is a Boolean constant. These constants cannot be modified while the program is running.

2. Variables

Variables are quantities that can change the value or data type during the running of the program. In Golang, variables are declared using the keyword var. The value of a variable can be modified anywhere in the program.

The naming convention of variables is the same as that of constants, starting with a letter or underscore, and can contain letters, numbers, and underscores. Variables can be data types such as character, string, boolean, and numeric. The following is sample code for some variables:

var age int = 18
var name string = "Alice"
var isMale bool = true

In the above code, age, name and isMale are an integer variable, a string variable and a Boolean variable respectively. The values ​​of these variables can be modified while the program is running.

The declaration and assignment of variables can be done separately or on the same line, as shown below:

var age int
age = 18

var name string = "Alice"

var isMale = true

3. The use of constants and variables

Constants and variables are in There are some differences in how the program is used.

1. The value of a constant needs to be determined at compile time, so the return value of a function cannot be used to initialize the constant. Variables can be initialized using the function's return value.
2. The declaration of a constant does not need to specify a type, and the compiler will automatically determine the type based on the assignment. The variable declaration must specify the type.

The following is an example code for using constants and variables:

package main

import (
    "fmt"
)

func main() {
    const PI = 3.14159
    var radius = 5.0
    var area float64

    area = PI * radius * radius

    fmt.Printf("半径为%f的圆的面积为%f
", radius, area)
}

In the above code, the value of the constant PI is 3.14159, and the value of the variable radius is 5.0. Through calculation, the circle can be obtained area and assign it to the variable area. Finally, the results are printed out through formatted output.

Summary:

This article details the difference and usage of constants and variables in Golang, and provides specific code examples. By studying and understanding these examples, readers can better master the use of constants and variables in Golang and lay the foundation for subsequent Golang programming. Golang's constants and variables are very important basic knowledge and are often used in practical applications. I hope readers can make better use of constants and variables and improve their programming abilities through studying this article.

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