What is the difference between Java functions and Go language functions?

The main difference between Java and Go language functions is: Creating functions: Java requires explicitly specifying types, while Go has type inference. Number of parameters: Fixed in Java, variable in Go (variable length parameters). Number of return values: Java can only return one, Go can return multiple (tuples). Pass by value and pass by reference: Java passes by value, Go passes by reference by default.

The difference between Java functions and Go language functions

Overview

Java and Go There are differences in the handling of functions between the two programming languages. This article will introduce the main differences between Java functions and Go language functions.

Creating functions

In Java, function declarations use the public static keyword as follows:

public static int sum(int a, int b) {
    return a + b;
}

In In the Go language, function declarations begin with the func keyword, as shown below:

func sum(a, b int) int {
    return a + b
}

Type inference

Java requires explicit The formula specifies the parameter type and return value type. The Go language has a type inference function that can automatically infer types based on parameter values.

func sum(a, b int) int {
    return a + b
}

Number of parameters

The number of parameters of a Java function must be fixed. The number of parameters of Go language functions can be variable, which is called "variable length parameters".

func sum(numbers ...int) int {
    total := 0
    for _, num := range numbers {
        total += num
    }
    return total
}

Number of return values

Java functions can only return one value. Go language functions can return multiple values, called "tuples".

func minMax(numbers ...int) (int, int) {
    min := numbers[0]
    max := numbers[0]
    for _, num := range numbers {
        if num < min {
            min = num
        }
        if num > max {
            max = num
        }
    }
    return min, max
}

Value passing and reference passing

Java functions use value passing, that is, a copy of the parameter value is passed. The Go language function uses reference passing by default, that is, the reference of the parameter is passed.

// Java
public static void changeValue(int value) {
    value = 100;
}

// Go
func changeValue(value *int) {
    *value = 100
}

Practical case

The following is a function that calculates the sum of two numbers, showing the difference between Java and Go language functions:

Java

public static int sum(int a, int b) {
    return a + b;
}

public static void main(String[] args) {
    int result = sum(10, 20);
    System.out.println(result); // 输出：30
}

Go Language

func sum(a, b int) int {
    return a + b
}

func main() {
    result := sum(10, 20)
    println(result) // 输出：30
}

As can be seen from this example, the parameter and return value types of Java functions must be explicitly specified. Go language functions support type inference and variable-length parameters.

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