CODEWITHSUNDEEP
javaswitch-statementrange
JavaNewbieeee
JavaNewbieeee

Reputation: 3

how to specify a range in switch case in java

Just started writing code in java and is learning normal logic operations. While using a switch case I wanted to specify a range and am not able to do it. switch (input){ case 0-20 : System.out.println("Your grade is F"); break;

            case 21-40 :
                System.out.println("Your grade is D");
                break;

            case 41-60 :
                System.out.println("Your grade is C");
                break;

            case 61-80 :
                System.out.println("Your grade is B");
                break;

            case 81-100 :
                System.out.println("Your grade is A");
                break;

Can anybody help me

Upvotes: 0

Views: 3043

Answers (1)

Old Dog Programmer
Old Dog Programmer

Reputation: 1251

The Java switch { case: wasn't designed to use ranges.

You can use a chain of if ... else if like this:

if (input >= 81) System.out.println ("Congratulations! Your grade is A");
else if (input >= 61) System.out.println ("Your grade is B");
else if (input >= 41) System.out.println ("Your grade is C);

Note this uses the suggestion from the comment from WJS. If you code several lines like this

else if (input >= 61 && input <= 80) ...

, there is a greater chance of making a typo and introducing a bug.

However, in this case, the fact that the range is always 20 points allows you to use a little math to fit a switch block:

int k = (input - 1) / 20; 
switch (k) { 
   case 0: 
       System.out.println ("Your grade is F. So sorry.");
   break;
   case 1:
       System.out.println ("Your grade is D");
   break;
   case 2:
       System.out.println ("Your grade is C");
       break;

and so on.

If I may, I'd like to offer some suggestions outside the scope of your question.

Instead of having multiple lines that all include "Your grade is ", calculate the grade as a single character or a String that contains a single character:

int k = (input - 1) / 20; 
char grade;
    switch (k) { 
       case 0: 
           grade = 'F';
       break;
       case 1:
           grade = 'D';
       break;
       case 2:
           grade = 'C';
           break;

and so on. It would be followed by

System.out.println ("Your grade is " + grade);

Here is a way to avoid both if ... else chain and switch block.

char [] grade = {'F','D','C','B','A'};
... 
int k = (input - 1) / 20;
System.out.println ("Your grade is " + grade [k]);

This assumes there is something to guard against the possibility that input will be less than zero or greater than 100.

Upvotes: 2

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