Objective-C - 嵌套的 switch 语句

可以将 switch 开关作为外部开关的语句序列的一部分。 即使内部和外部 switch 的 case 常量包含公共值，也不会发生冲突。

语法

嵌套 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 */
}

示例

#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;
}

当上面的代码被编译和执行时，会产生如下结果 −

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

objective_c_decision_making.html