// Question 1. What will be displayed on the screen? package main import "fmt" func main() { s := "Hello world" s[0] = "h" if err != nil { fmt.Println("Error", err) } fmt.Println(s) }

The code will not compile. In Go, strings are immutable, so you cannot assign a value to an individual byte of a string, for example, s[0] = "h" will cause a compilation error.

Additionally, the variable err is not declared, so the condition if err != nil also will cause an error.

The correct way to modify a string is to create a new string, for example:

package main

import "fmt"

func main() {
    s := "Hello world"
    s = "h" + s[1:]
    fmt.Println(s) // will output "hello world"
}

Thus, the original code will lead to compilation errors and will not output anything.