How Does Variable Scope and Shadowing Enhance Code Control and Data Integrity in Go?

package main

import "fmt"

func main() {
    i := 10 // scope: main
    j := 4
    // Shadowing i within this block
    for i := 'a'; i < 'b'; i++ {
        // Access shadowed i and j
        fmt.Println(i, j) // 97 4
    }
    // Original i comes into scope
    fmt.Println(i, j) // 10 4

    // Shadowing i again within the if block
    if i := "test"; len(i) == j {
        // Shadowed i with string "test"
        fmt.Println(i, j) // test 4
    } else {
        // Shadowed i again with string "test40"
        fmt.Println(i, j) // test 40
    }
    // Original i comes into scope
    fmt.Println(i, j) // 10 4
}

package main

import "fmt"

func main() {
    i := 1
    j := 2
    // Create new scope with { } block
    {
        // Shadow i with a new local variable
        i := "hi"
        // Increment j
        j++
        fmt.Println(i, j) // hi 3
    }
    // Original i comes into scope
    fmt.Println(i, j) // 1 3
}

package main

import "fmt"

func fun(i int, j *int) {
    i++    // Implicitly shadowing (used as local)
    *j++   // Explicitly shadowing (used as global)
    fmt.Println(i, *j) // 11 21
}

func main() {
    i := 10 // scope: main
    j := 20
    fun(i, &j)
    fmt.Println(i, j) // 10 21
}

package main

import "fmt"

var i int = 1 // Global variable

func main() {
    j := 2
    fmt.Println(i, j) // 1 2

    // Shadowing global i
    i := 10
    fmt.Println(i, j) // 10 2

    fun(i, j) // 10 2
}

func fun(i, j int) {
    fmt.Println(i, j) // 10 2
}