嵌套的switch语句（nested switch statements）

可以将开关作为外部开关的语句序列的一部分。 即使内部和外部交换机的大小写常量包含公共值，也不会产生冲突。

语法 (Syntax)

nested switch语句的语法如下 -

switch(ch1) {
   case 'A': 
      printf("This A is part of outer switch" );
      switch(ch2) {
         case 'A':
            printf("This A is part of inner switch" );
            break;
         case 'B': /* case code */
      }
      break;
   case 'B': /* case code */
}

例子 (Example)

#import <Foundation/Foundation.h>
int main () {
   /* local variable definition */
   int a = 100;
   int b = 200;
   switch(a) {
      case 100: 
         NSLog(@"This is part of outer switch\n", a );
         switch(b) {
            case 200:
               NSLog(@"This is part of inner switch\n", a );
         }
   }
   NSLog(@"Exact value of a is : %d\n", a );
   NSLog(@"Exact value of b is : %d\n", b );
   return 0;
}

编译并执行上述代码时，会产生以下结果 -

2013-09-07 22:09:20.947 demo[21703] This is part of outer switch
2013-09-07 22:09:20.948 demo[21703] This is part of inner switch
2013-09-07 22:09:20.948 demo[21703] Exact value of a is : 100
2013-09-07 22:09:20.948 demo[21703] Exact value of b is : 200