Passing Arrays to Functions in Go

Go Arrays

If you want to pass an array as a parameter to a function, you need to declare the formal parameter as an array in the function definition. You can declare it in one of the following two ways:

Method 1

Formal parameter with specified array size:

void myFunction(param [10]int)
{
.
.
.
}

Method 2

Formal parameter without specified array size:

void myFunction(param []int)
{
.
.
.
}

Example

Let's look at the following example. The function receives an integer array parameter and another parameter specifying the number of elements in the array, and returns the average:

Example

func getAverage(arr []int, size int) float32
{
   var i int
   var avg, sum float32  

   for i = 0; i < size; ++i {
      sum += arr[i]
   }

   avg = sum / size

   return avg;
}

Next, let's call this function:

Example

package main

import "fmt"

func main() {
   /* Array length is 5 */
   var balance = [5]int {1000, 2, 3, 17, 50}
   var avg float32

   /* Pass the array to the function */
   avg = getAverage(balance, 5)

   /* Print the returned average */
   fmt.Printf("Average value is: %f ", avg)
}
func getAverage(arr [5]int, size int) float32 {
   var i, sum int
   var avg float32  

   for i = 0; i < size; i++ {
      sum += arr[i]
   }

   avg = float32(sum) / float32(size)

   return avg;
}

The output of the above example is:

Average value is: 214.399994

In the above example, we used a formal parameter without specifying the array size.

Floating-point calculations may have some deviations in the output. You can also convert to integers to set the precision.

Example

package main
import (
    "fmt"
)
func main() {
    a := 1.69
    b := 1.7
    c := a * b      // The result should be 2.873
    fmt.Println(c)  // Outputs 2.8729999999999998
}

Setting a fixed precision:

Example

package main
import (
    "fmt"
)
func main() {
    a := 1690            // Represents 1.69
    b := 1700            // Represents 1.70
    c := a * b           // The result should be 2873000 representing 2.873
    fmt.Println(c)       // Internal encoding
    fmt.Println(float64(c) / 1000000) // Display
}

Go Arrays