switch var1 {
  case val1:
    ...
  case val2:
    ...
  default:
    ...
}

package main

import "fmt"

func main() {
  /* 定义局部变量 */
  var grade string = "B"
  var marks int = 90

  switch marks {
   case 90: grade = "A"
   case 80: grade = "B"
   case 50,60,70 : grade = "C"
   default: grade = "D" 
  }

  switch {
   case grade == "A" :
     fmt.Printf("优秀!\n" )   
   case grade == "B", grade == "C" :
     fmt.Printf("良好\n" )   
   case grade == "D" :
     fmt.Printf("及格\n" )   
   case grade == "F":
     fmt.Printf("不及格\n" )
   default:
     fmt.Printf("差\n" );
  }
  fmt.Printf("你的等级是 %s\n", grade );   
}

switch x.(type){
  case type:
    statement(s);   
  case type:
    statement(s); 
  /* 你可以定义任意个数的case */
  default: /* 可选 */
    statement(s);
}

package main

import "fmt"

func main() {
  var x interface{}
   
  switch i := x.(type) {
   case nil:   
     fmt.Printf(" x 的类型 :%T",i)        
   case int:   
     fmt.Printf("x 是 int 型")            
   case float64:
     fmt.Printf("x 是 float64 型")      
   case func(int) float64:
     fmt.Printf("x 是 func(int) 型")           
   case bool, string:
     fmt.Printf("x 是 bool 或 string 型" )    
   default:
     fmt.Printf("未知型")   
  }  
}