CODEWITHSUNDEEP
javacharswitch-statement
GlassZee
GlassZee

Reputation: 1127

Java Switch Statement - Is "or"/"and" possible?

I implemented a font system that finds out which letter to use via char switch statements. There are only capital letters in my font image. I need to make it so that, for example, 'a' and 'A' both have the same output. Instead of having 2x the amount of cases, could it be something like the following:

char c;

switch(c){
case 'a' & 'A': /*get the 'A' image*/; break;
case 'b' & 'B': /*get the 'B' image*/; break;
...
case 'z' & 'Z': /*get the 'Z' image*/; break;
}

Is this possible in java?

Upvotes: 86

Views: 148035

Answers (6)

kerner1000
kerner1000

Reputation: 3558

Enhanced switch/ case / Switch with arrows syntax (Since Java 13):

char c;
switch (c) {
    case 'A', 'a' -> {} // c is either 'A' or 'a'.
    case ...
}

Upvotes: 4

Abhijeet
Abhijeet

Reputation: 8771

Observations on an interesting Switch case trap --> fall through of switch

"The break statements are necessary because without them, statements in switch blocks fall through:" Java Doc's example

Snippet of consecutive case without break:

    char c = 'A';/* switch with lower case */;
    switch(c) {
        case 'a':
            System.out.println("a");
        case 'A':
            System.out.println("A");
            break;
    }

O/P for this case is:

A

But if you change value of c, i.e., char c = 'a';, then this get interesting.

O/P for this case is:

a A

Even though the 2nd case test fails, program goes onto print A, due to missing break which causes switch to treat the rest of the code as a block. All statements after the matching case label are executed in sequence.

Upvotes: 2

Matt Ball
Matt Ball

Reputation: 359966

You can use switch-case fall through by omitting the break; statement.

char c = /* whatever */;

switch(c) {
    case 'a':
    case 'A':
        //get the 'A' image;
        break;
    case 'b':
    case 'B':
        //get the 'B' image;
        break;
    // (...)
    case 'z':
    case 'Z':
        //get the 'Z' image;
        break;
}

...or you could just normalize to lower case or upper case before switching.

char c = Character.toUpperCase(/* whatever */);

switch(c) {
    case 'A':
        //get the 'A' image;
        break;
    case 'B':
        //get the 'B' image;
        break;
    // (...)
    case 'Z':
        //get the 'Z' image;
        break;
}

Upvotes: 218

Manan Pancholi
Manan Pancholi

Reputation: 103

From what I understand about your question, before passing the character into the switch statement, you can convert it to lowercase. So you don't have to worry about upper cases because they are automatically converted to lower case. For that you need to use the below function:

Character.toLowerCase(c);

Upvotes: 1

scorpiodawg
scorpiodawg

Reputation: 5752

The above are all excellent answers. I just wanted to add that when there are multiple characters to check against, an if-else might turn out better since you could instead write the following.

// switch on vowels, digits, punctuation, or consonants
char c; // assign some character to 'c'
if ("aeiouAEIOU".indexOf(c) != -1) {
  // handle vowel case
} else if ("!@#$%,.".indexOf(c) != -1) {
  // handle punctuation case
} else if ("0123456789".indexOf(c) != -1) {
  // handle digit case
} else {
  // handle consonant case, assuming other characters are not possible
}

Of course, if this gets any more complicated, I'd recommend a regex matcher.

Upvotes: 7

Dinah
Dinah

Reputation: 54027

Above, you mean OR not AND. Example of AND: 110 & 011 == 010 which is neither of the things you're looking for.

For OR, just have 2 cases without the break on the 1st. Eg:

case 'a':
case 'A':
  // do stuff
  break;

Upvotes: 24

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