Function Arguments in Golang

In Golang, functions are groups of statements used to perform tasks, with optional returns. Go supports two main ways to pass arguments: Pass by Value and Pass by Reference. By default, Go uses pass-by-value.

Basic Terms in Parameter Passing to Functions:

• Actual Parameters: The arguments passed to a function.
• Formal Parameters: The parameters received by the function.

Example

package main
import "fmt"

// Attempts to modify the value of num
func modify(num int) {
 num = 50
}

func main() {
 num := 20
 fmt.Printf("Before, num = %d\n", num)
 modify(num)
 fmt.Printf("After, num = %d\n", num)
}

In this example, num remains unchanged after calling modify since it’s passed by value.

Syntax

func functionName(param Type) {
 // function body # Call By Value
}

func functionName(param *Type) {
 // function body # Call By Reference
}

Call By Value

In call-by-value, a copy of the actual parameter’s value is passed. Changes made in the function don’t affect the original variable.

Syntax

func functionName(param Type) {
 // function body
}

Example:

Before, num = 20
After, num = 20

The value remains the same, as changes inside modify don’t impact num in main.

Call By Reference

In call-by-reference, a pointer to the actual parameter is passed, so any changes inside the function reflect on the original variable.

Syntax

func functionName(param *Type) {
 // function body
}

Example:

Before, num = 20
After, num = 50

Since num is passed by reference, modify changes its value, which is reflected in main.