Java nested if to switch statement

Question

I'm having trouble transforming the following nested if statement below, into an equivalent switch statement. If anyone can give me some advice, it would be appreciated.

if (num1 == 5)
    myChar = ‘A’;
else
if (num1 == 6 )
    myChar = ‘B’;
else
if (num1 = 7)
    myChar = ‘C’;
else
    myChar = ‘D’;

Please show any attempt at a switch statement you've made, along with any problems you've encountered. — rgettman
– rgettman, Commented Oct 29, 2015 at 19:17
Note: These if blocks are not nested. They are chained. — kdbanman
– kdbanman, Commented Oct 29, 2015 at 19:26
For something like this he could also use a character array over a switch statement. char [] chars = {'A','B','C','D'}; int index = num1-5; myChar = chars[index]; — Clark Kent
– Clark Kent, Commented Oct 29, 2015 at 19:30

Eric Hotinger · Accepted Answer · 2015-10-29 19:19:03Z

2

Pretty straightforward, just use the number as the thing you want to switch on. Your else case becomes the default case.

switch (num1) {
    case 5:
        myChar = 'A';
        break;
    case 6:
        myChar = 'B';
        break;
    case 7:
        myChar = 'C';
        break;
    default:
        myChar = 'D';
        break;
}

answered Oct 29, 2015 at 19:19

Eric Hotinger

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Comments

Paul Boddington · Accepted Answer · 2015-10-29 19:34:16Z

1

If the values follow a simple pattern like this, you don't need a switch at all. For example you can do

myChar = num1 >= 5 && num1 <= 7 ? (char) ('A' + num1 - 5) : 'D';

If num1 is always 5, 6, 7 or 8 you can just do

myChar = (char) ('A' + num1 - 5);

answered Oct 29, 2015 at 19:34

Paul Boddington

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Comments

Tahar Bakir · Accepted Answer · 2015-10-29 20:27:25Z

1

For more details chek the documentation : https://docs.oracle.com/javase/tutorial/java/nutsandbolts/switch.html

switch(num1){
 case 5:
   myChar = ‘A’;
   break;
 case 6:
   myChar = ‘B’;
   break;
 case 7:
   myChar = ‘C’;
   break;
 default:
   myChar = ‘D’;
}

edited Oct 29, 2015 at 20:27

answered Oct 29, 2015 at 19:22

Tahar Bakir

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1 Comment

Clark Kent Over a year ago

This would return either A or D only. You should change the values of your case statements.

Tyrone Annor · Accepted Answer · 2020-04-25 14:04:40Z

0

In JDK 12, extended switch will allow you to assign a char value directly to the switch. Construct your switch as such:

char myChar = switch(num1) {
    case 5 -> 'A';
    case 6 -> 'B'; 
    case 7 -> 'C';
    default -> 'D';
}

answered Apr 25, 2020 at 14:04

Tyrone Annor

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1 Comment

Dimitrios K. Over a year ago

It's good that you showcase a fairly new feature in Java, but I think it'd be worth to also add an example for pre-java 12.

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