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deepakdeepak
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switch does not work with complex types
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‎QUESTIONS.md‎

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@@ -76,5 +76,25 @@
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persons[2] = new Person()
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```
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- why does switch not work with complex types ?
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when can add a complex type to a hash and its hashCode and equals method is used
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why not use equals for switch ?
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also how does type-safety work for switch ?
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```java
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Person p1 = new Person("p1");
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Person p2 = new Person("p2");
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// does not work
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switch (p2) {
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case p1:
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System.out.println("switch to p1");
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break;
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case p2:
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System.out.println("switch to p1");
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break;
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default:
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System.out.println("nothing to switch");
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}
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```
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‎src/Main.java‎

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@@ -36,5 +36,61 @@ public static void main(String[] args) {
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// persons[2] = p2;
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System.out.println("persons: " + Arrays.toString(persons));
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// does not work
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// https://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html
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// A switch works with the byte, short, char, and int primitive data types.
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// It also works with enumerated types (discussed in Enum Types), the String class,
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// and a few special classes that wrap certain primitive types:
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// Character, Byte, Short, and Integer (discussed in Numbers and Strings).
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// why is this rule ? when adding to map works with the object's hashCode and equals ?
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// switch (p2) {
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// case p1:
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// System.out.println("switch to p1");
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// break;
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// case p2:
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// System.out.println("switch to p1");
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// break;
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// default:
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// System.out.println("nothing to switch");
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// }
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System.out.println("8'th month is: " + monthName(8));
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}
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public static String monthName(int month) {
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String monthString;
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// is type-safe so `case "10"` will throw a type error
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switch (month) {
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case 1: monthString = "January";
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break;
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case 2: monthString = "February";
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break;
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case 3: monthString = "March";
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break;
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case 4: monthString = "April";
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break;
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case 5: monthString = "May";
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break;
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case 6: monthString = "June";
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break;
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case 7: monthString = "July";
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break;
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case 8: monthString = "August";
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break;
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case 9: monthString = "September";
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break;
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case 10: monthString = "October";
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break;
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case 11: monthString = "November";
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break;
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case 12: monthString = "December";
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break;
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default: monthString = "Invalid month";
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break;
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}
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return monthString;
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}
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}

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