:= in golang

package main

import "fmt"

func main() {
    // Declare and initialize a variable 'x' with the value 10
    x := 10

    // Declare a variable 'y' without initializing it
    var y int

    // Assign the value of 'x' to 'y'
    y = x

    // Print the values of 'x' and 'y'
    fmt.Println("x:", x, "y:", y)

    // Declare and initialize a new variable 'z' with the value 5
    z := 5

    // Perform an arithmetic operation and assign the result to 'z'
    z += x

    // Print the updated value of 'z'
    fmt.Println("z:", z)
}