Java 演算子

class Sample1_06_1 {
   public static void main (String[] args) {
      
      //算術演算子の活用
      
      int numberX = 8 ;
      int numberY = 4 ;
      int numberZ = 5 ;
      String stNumberX = "1";
      String stNumberY = "2";
      
      //『 + 』
      int answer1 = numberX + numberY ;
      System.out.println("answer1：" + answer1);
      
      //『 - 』
      int answer2 = numberX - numberY ;
      System.out.println("answer2：" + answer2);
      
      //『 * 』
      int answer3 = numberX * numberY ;
      System.out.println("answer3：" + answer3);
      
      //『 / 』
      int answer4 = numberX / numberY ;
      System.out.println("answer4：" + answer4);
      
      //『 / 』（割り切れない場合）
      int answer5 = numberX / numberZ ;
      System.out.println("answer5：" + answer5);
      
      //『 % 』
      int answer6 = numberX % numberZ ;
      System.out.println("answer6：" + answer6);
      
      // 符号反転
      int answer7 = -answer6 ;
      System.out.println("answer7：" + answer7);
      
      //『 ○++ 』
      int answer8 = numberX++ ;
      System.out.println("answer8：" + answer8);
      System.out.println("（ numberX：" + numberX + " ）");
      
      //『 ++○ 』
      int answer9 = ++numberY ;
      System.out.println("answer9：" + answer9);
      System.out.println("（ numberY：" + numberY + " ）");
      
      //『 +1 』と『 ++ 』の使い分けの注意
      int answer10 = numberZ + 1 ;
      System.out.println("answer10：" + answer10);
      System.out.println("（ numberZ：" + numberZ + " ）");
      
      //『 -- 』
      int answer11 = numberZ-- ;
      System.out.println("answer11：" + answer11);
      System.out.println("（ numberZ：" + numberZ + " ）");
      
      //『 + 』（文字の結合）
      String answer12 = stNumberX + stNumberY ;
      System.out.println("answer12：" + answer12);
      
   }
}

class Sample1_06_2 {
   public static void main (String[] args) {
      
      //代入演算子の活用
      
      //『 += 』
      int number0 = 10 ;
      number0 += 3 ;
      System.out.println("number0：" + number0);
      
      //『 変数x += 3 』は『 変数x = 変数x + 3 』と同じ意味
      int number1 = 10 ;
      number1 = number1 + 3 ;
      System.out.println("number1：" + number1 + " ※number0と同じ値になる");
      
      //『 -= 』
      int number2 = 10 ;
      number2 -= 3 ;
      System.out.println("number2：" + number2);
      
      //『 *= 』
      int number3 = 10 ;
      number3 *= 3 ;
      System.out.println("number3：" + number3);
      
      //『 /= 』（割り切れない場合）
      int number4 = 10 ;
      number4 /= 3 ;
      System.out.println("number4：" + number4);
      
      //『 %= 』
      int number5 = 10 ;
      number5 %= 3 ;
      System.out.println("number5：" + number5);
      
      //『 += 』（文字の結合）
      String stNumber6 = "10" ;
      stNumber6 += "3" ;
      System.out.println("stNumber6：" + stNumber6);
      
   }
}

class Sample1_06_3 {
   public static void main (String[] args) {
      
      //関係演算子の活用
      
      int numberX = 8 ;
      int numberY = 8 ;
      int numberZ = 7 ;
      char chNumberX = 'あ';
      char chNumberY = 'あ';
      
      //『 == 』
      boolean logicalValue1 = numberX == numberY ;
      System.out.println("logicalValue1：" + logicalValue1);
      
      //『 != 』
      boolean logicalValue2 = numberX != numberY ;
      System.out.println("logicalValue2：" + logicalValue2);
      
      //『 > 』
      boolean logicalValue3 = numberX > numberZ ;
      System.out.println("logicalValue3：" + logicalValue3);
      
      //『 >= 』
      boolean logicalValue4 = numberX >= numberY ;
      System.out.println("logicalValue4：" + logicalValue4);
      
      //『 < 』
      boolean logicalValue5 = numberX < numberZ ;
      System.out.println("logicalValue5：" + logicalValue5);
      
      //『 <= 』
      boolean logicalValue6 = numberX <= numberY ;
      System.out.println("logicalValue6：" + logicalValue6);
      
      //『 == 』（関係代名詞は数値以外にも使用可能：char型）
      boolean logicalValue7 = chNumberX == chNumberY ;
      System.out.println("logicalValue7：" + logicalValue7);
      
      //『 == 』（関係代名詞は数値以外にも使用可能：boolean型）
      boolean logicalValue8 = logicalValue1 == logicalValue2 ;
      System.out.println("logicalValue8：" + logicalValue8);
      
   }
}

class Sample1_06_4 {
   public static void main (String[] args) {
      
      //論理演算子の活用
      
      int numberX = 8 ;
      int numberY = 4 ;
      int numberZ = 5 ;
      
      //『 && 』
      boolean logicalValue1 = numberX != numberY && numberY > numberZ ;
      System.out.println("logicalValue1：" + logicalValue1);
      
      //『 || 』
      boolean logicalValue2 = numberX != numberY || numberY > numberZ ;
      System.out.println("logicalValue2：" + logicalValue2);
      
      //『 ^ 』
      boolean logicalValue3 = numberX != numberY ^ numberY > numberZ ;
      System.out.println("logicalValue3：" + logicalValue3);
      
      // 反転
      boolean logicalValue4 = !logicalValue3 ;
      System.out.println("logicalValue4：" + logicalValue4);
      
   }
}

＜演習：Ex1_06_1＞
以下、 ①～⑤でそれぞれどのようなデータが画面に表示されるでしょう？
① int answer1 = 3 + ( 7 % 4 ) / 2 ;
System.out.println( answer1 );

② int calc2 = 10 ;
int answer2 = ++calc2 ;
System.out.println( calc2 );
System.out.println( answer2 );

③ int calc3 = 10 ;
int answer3 = calc3++ ;
System.out.println( calc3 );
System.out.println( answer3 );

④ int calc4 = 10 ;
int answer4 = calc4 + 1;
System.out.println( calc4 );
System.out.println( answer4 );

⑤ System.out.println( “1” + “6” );

＜演習：Ex1_06_2＞
以下、 ①～④でそれぞれどのようなデータが画面に表示されるでしょう？
① boolean answer1 = 5 == 3 + 2 ;
System.out.println( answer1 );

② boolean answer2 = 5 >= 3 + 2 ;
System.out.println( answer2 );

③ boolean answer3 = 5 >= 3 + 2 && 10 % 3 != 1 ;
System.out.println( answer3 );

④ boolean answer4 = ( 5 >= 3 + 2 || 2 + 8 != 9 ) && !( 6 == 2 + 4 ) ;
System.out.println( answer4 );