CODEWITHSUNDEEP
java
Christopher Babayans
Christopher Babayans

Reputation: 57

What is wrong with my understanding of switch statements?

Logically, I would think the answer should be 0. The print out is 2.

public class Switch{
public static void main(String[] args){

int x = 3; int y = 4;

  switch (x + 3) {
    case 6: y = 0;
    case 7: y = 1; 
    default: y += 1;
   }
System.out.print(y);
}
}

This is how I would think the code should run:

1) add x + 3. The answer is 6.

2) case 6 correlates with answer 6. This results in 0 being the new value for 6.

3) we ignore case 7 and default because case 6 fit the needs.

4) System prints out the new value for y, which is 0.

This is where I am wrong, because 2 is printed out. Where is my thinking wrong, and what am I missing in my understanding about switch statements?

Upvotes: 1

Views: 90

Answers (2)

Mureinik
Mureinik

Reputation: 311018

In a switch you "fall through" the cases, starting from the one matched. So here, you enter case 6, then case 7 and then default. This behavior can be prevented with the break keyword:

switch (x + 3) {
    case 6: 
        y = 0;
        break;
    case 7:
        y = 1; 
        break;
    default:
        y += 1;
        break;
}

Upvotes: 1

Erik
Erik

Reputation: 3636

Once a Case in a Switch statement is selected, code execution is just straight down from there, which means that it´s executing all of the cases. If you don´t want that, use Break statements:

switch (x + 3) {
    case 6: y = 0; break;
    case 7: y = 1; break;
    default: y += 1; break;
   }

Upvotes: 3

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