回答編集履歴
1
列挙
test
CHANGED
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@@ -7,3 +7,101 @@
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"ce"の入力に対しては現在のmsgの状態などから戻る状態を判断してループの最初に戻すくらいなのでは？
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10
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私だったら演算子の列挙型を作ってしまいたくなります。
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```java
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//
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enum Operator {
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PLUS {
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@Override
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public BigDecimal calculate(String num1, String num2) {
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return new BigDecimal(num1).add(new BigDecimal(num2));
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}
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},
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MINUS {
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@Override
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public BigDecimal calculate(String num1, String num2) {
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return new BigDecimal(num1).subtract(new BigDecimal(num2));
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}
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},
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MULTIPLY {
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@Override
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public BigDecimal calculate(String num1, String num2) {
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return new BigDecimal(num1).multiply(new BigDecimal(num2));
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}
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},
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DIVIDE {
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@Override
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public BigDecimal calculate(String num1, String num2) {
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return new BigDecimal(num1).divide(new BigDecimal(num2), 20, BigDecimal.ROUND_HALF_UP);
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}
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};
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71
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abstract public BigDecimal calculate(String num1, String num2);
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public static Operator of(String operator) {
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switch (operator) {
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case "+":
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return PLUS;
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case "-":
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return MINUS;
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case "*":
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return MULTIPLY;
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90
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case "/":
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return DIVIDE;
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96
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default:
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98
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throw new IllegalArgumentException("演算子でありません。");
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100
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101
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}
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102
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103
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}
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104
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105
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}
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106
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107
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```
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