Pascal - 巢狀 Case 語句

在外部 case 語句 的語句序列中，可以有一個 case 語句。即使內部和外部 case 的 case 常量 包含常見值，也不會出現衝突。

語法

巢狀 case 語句的語法如下 −

case (ch1) of
   'A': begin
      writeln('This A is part of outer case' );
         case(ch2) of
            'A': writeln('This A is part of inner case' );
            'B': (* case code *)
            ...
         end; {end of inner case}
      end; (* end of case 'A' of outer statement *)
   'B': (* case code *)
   'C': (* case code *)
   ...
end; {end of outer case}

示例

以下程式說明了該概念。

program checknestedCase;
var
   a, b: integer;
begin
   a := 100;
   b := 200;
   
   case (a) of
      100: begin
         writeln('This  is part of outer statement' );
         case (b) of
            200: writeln('This  is part of inner statement' );
            end;
         end; 
      end;
   
   writeln('Exact value of a is : ', a );
   writeln('Exact value of b is : ', b );
end.

當編譯並執行上述程式碼時，它會產生以下結果 −

This is part of outer switch
This is part of inner switch
Exact value of a is: 100
Exact value of b is: 200