Go language function

Go language function

A function is a basic block of code that is used to perform a task.

The Go language has at least one main() function.

You can divide different functions by functions, and logically each function performs the specified task.

The function declaration tells the compiler the name of the function, the return type, and the parameters.

The Go Language Standard Library provides a variety of built-in functions that are available. F or example, a len() function can accept different type parameters and return the length of that type. If we pass in a string, we return the length of the string, and if we pass in a number, the number of functions contained in the array is returned.

The function definition

The Go language function is defined in the following format:

func function_name( [parameter list] ) [return_types]{
   函数体
}

Function definition parsing:

• func: The function is declared by func
• function_name: Function names, function names, and a list of parameters make up the function signature.
• parameter list: A list of parameters, which act like a placeholder, and when a function is called, you can pass the value to the argument, which is called the actual argument. T he list of parameters specifies the type, order, and number of parameters. Arguments are optional, which means that functions can also not contain arguments.
• return_types: Return type, function returns a column of values. r eturn_types is the data type of the column value. Some features do not require a return value, in which case return_types is not required.
• Function body: A collection of code defined by a function.

Instance

The following example is the code for the max() function, which passes in two integer parameters, num1 and num2, and returns the maximum values for both parameters:

/* 函数返回两个数的最大值 */
func max(num1, num2 int) int{
   /* 声明局部变量 */
   result int

   if (num1 > num2) {
      result = num1
   } else {
      result = num2
   }
   return result 
}

The function is called

When you create a function, you define what the function needs to do and perform the specified task by calling the change function.

Call the function, pass arguments to the function, and return values, such as:

package main

import "fmt"

func main() {
   /* 定义局部变量 */
   var a int = 100
   var b int = 200
   var ret int

   /* 调用函数并返回最大值 */
   ret = max(a, b)

   fmt.Printf( "最大值是 : %d\n", ret )
}

/* 函数返回两个数的最大值 */
func max(num1, num2 int) int {
   /* 定义局部变量 */
   var result int

   if (num1 > num2) {
      result = num1
   } else {
      result = num2
   }
   return result 
}

The above example calls the max() function in the main() function, and the result is:

最大值是 : 200

The function returns more than one value

The Go function can return multiple values, such as:

package main

import "fmt"

func swap(x, y string) (string, string) {
   return y, x
}

func main() {
   a, b := swap("Mahesh", "Kumar")
   fmt.Println(a, b)
}

The above examples perform as follows:

Kumar Mahesh

Function arguments

If a function uses an argument, the variable can be called a parameter of a function.

A parameter is like a local variable defined in a function body.

A function can be called to pass arguments in two ways:

By default, the Go language uses value delivery, which means that the actual parameters are not affected during the call.

Function usage