Advent of Code 2021 Day 2: Dive!

package main  
  
import (  
   "bufio"  
 "fmt" "log" "os" "strconv" "strings")  
  
func part1(cmds []Cmd) {  
   horz := 0  
 depth := 0  
 for _, cmd := range cmds {  
      switch cmd.Dir {  
      case "forward":  
         horz += cmd.N  
      case "up":  
         depth -= cmd.N  
      case "down":  
         depth += cmd.N  
      }  
  
   }  
   fmt.Println(horz*depth)  
}  
  
func part2(cmds []Cmd) {  
   horz := 0  
 depth := 0  
 aim := 0  
 for _, cmd := range cmds {  
      switch cmd.Dir {  
      case "forward":  
         horz += cmd.N  
         depth += aim*cmd.N  
      case "up":  
         aim -= cmd.N  
      case "down":  
         aim += cmd.N  
      }  
  
   }  
   fmt.Println(horz*depth)  
}  
  
type Cmd struct {  
   Dir string  
 N   int  
}  
  
func main() {  
   f, err := os.Open("input.txt")  
   if err != nil {  
      log.Fatal(err)  
   }  
   scanner := bufio.NewScanner(f)  
   var cmds []Cmd  
 for scanner.Scan() {  
      line := scanner.Text()  
      parts := strings.Split(line, " ")  
      dir := parts[0]  
      n, err := strconv.Atoi(parts[1])  
      if err != nil {  
         panic("nope")  
      }  
      cmds = append(cmds, Cmd{  
         Dir: dir,  
 N:   n,  
 })  
   }  
  
   part1(cmds)  
   part2(cmds)  
}