The func keyword is followed by comma-separated data types for the parameters of that function within parentheses. Additionally, we specify the return data type for the expected function or set of functions, if applicable.

An example can help illustrate this concept:

index


              12345678910111213141516
            
package main
import "fmt"

func nTimes(n int, msg string) {
    for i := 0; i < n; i++ {
        fmt.Println(msg)
    }
}

func printFiveTimes(msg string, show func(int, string)) {
    show(5, "Hello World")
}

func main() {
    printFiveTimes("HelloWorld", nTimes)
}

In the example above, we pass a function named nTimes as an argument to the printFiveTimes function. The data type for the show parameter in the definition of the printFiveTimes function is func(int, string), which corresponds to the definition of the nTimes function, i.e., nTimes(n int, msg string).

Now, let's take a look at an example of a function with a return value:

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package main
import "fmt"

// A factorial is the product of all the numbers from 1 up till n
// For-example factorial of 5 is 1x2x3x4x5, which is 120
func factorial(n int) int {
    var result int = 1;
    for i := 2; i <= n; i++ {
        result *= i
    }
    return result
}

func eval(n int, oper func(int) int) int {
    return oper(n)
}

func main() {
    fmt.Println(eval(5, factorial))
}

Everything was clear?

Thanks for your feedback!

Section 4. Chapter 6

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Course Content

Introduction to GoLang

1. Getting Started

2. Data Types

Integers Floating-Point Numbers Booleans Runes Strings Basic Type Casting String Formatting Challenge: String Formatting Practice

3. Control Structures

Comparison Operators Conditional Statements Conditional Chaining Logical Operators Switch Statement For Loop Break Statement Challenge: Practicing For Loop

4. Functions

5. Arrays and Slices

6. Intro to Structs & Maps

Creating Structs Creating Instances of Structs Data in Structs What are Maps?Map Declaration and Initialization Accessing Map Values Deleting Keys From Maps Challenge: Creating a Structure

Passing Functions as Arguments

Another useful feature is the ability to pass functions as arguments to other functions.

As a reminder, the fundamental syntax of a function with parameters is as follows:

python

We use the following syntax to specify the data type of the parameter when passing it to a function:

python

An example can help illustrate this concept:

index


              12345678910111213141516
            
package main
import "fmt"

func nTimes(n int, msg string) {
    for i := 0; i < n; i++ {
        fmt.Println(msg)
    }
}

func printFiveTimes(msg string, show func(int, string)) {
    show(5, "Hello World")
}

func main() {
    printFiveTimes("HelloWorld", nTimes)
}

Now, let's take a look at an example of a function with a return value:

index


              1234567891011121314151617181920
            
package main
import "fmt"

// A factorial is the product of all the numbers from 1 up till n
// For-example factorial of 5 is 1x2x3x4x5, which is 120
func factorial(n int) int {
    var result int = 1;
    for i := 2; i <= n; i++ {
        result *= i
    }
    return result
}

func eval(n int, oper func(int) int) int {
    return oper(n)
}

func main() {
    fmt.Println(eval(5, factorial))
}

Everything was clear?

Thanks for your feedback!

Section 4. Chapter 6