Uzum - 1

• What will this output and why? go/puzzles

Задача: (код без описания) go/basics

func main() {
s:="test "
println(s[0])
s[0] = 'A'
println(s)
}

• What will this output and why? go/puzzles

Задача: (код без описания) go/basics

func main() {
  a := make(chan int, 1)
  for i := 0; i < 5; i++ {
    select {
    case <-a:
      fmt.Println(i)
    case a <- i:
      fmt.Println(i)
    }
  }
}

• What will this output? go/puzzles

Задача: (код без описания) go/basics

func main() {
  var arr = []int{1, 2, 3, 4, 5}

  for i := range arr {
    defer fmt.Printf("%d ", arr[i])
  }
}

And this way?

Explain why and why the output differs before and after Go v1.22. How to fix it if Go <v1.22.

• What will this output and why? go/puzzles

Задача: (код без описания) go/basics

func main() {
  slice := []string{"A ", "B ", "C "}
  addElem(slice[1:2], "X ")
  fmt.Println(slice)
}

func addElem(slice []string, elem string) {
  slice = append(slice, elem)
}

• What will be the order and why? go/puzzles

Задача: (код без описания) go/basics

func main() {
  m := map[string]int{
    "a ": 1,
    "b ": 2,
    "c ": 3,
    "d ": 4,
  }

  for k, v := range m {
    fmt.Printf("Key: %s, Value: %d\n ", k, v)
  }

  for k, v := range m {
    fmt.Printf("Key: %s, Value: %d\n ", k, v)
  }
}

• Live coding task: Implement a function that multiplexes channels and returns a result channel without waiting for them to merge. go/channels

Задача: (код без описания) go/basics

// fan in / channel multiplexer / channel merge
// takes all values from all input channels and writes them to the result channel
// the pointer to the result channel must be obtained immediately
// after all input channels close - the result channel must also be closed
func merge(chans ...chan int) chan int {
  // write here
}

System design: design the architecture of a population census system for China.

Задача: there is no read load, and after clarifying the scope of requirements they will try to change them. architecture/system-design