Char Tester in java (uppercase A-Z,lowercase a-z,digit 0-9,other)

Question

I'm trying to make a program that tells me weather the char i put in arguments is uppercase or lowercase or a digit from 0 to 9 or other! I'm having errors in my code:

public class CharsTester {


    public static void main(String[] args) {


         char input;

         if (input.matches("^[a-zA-Z]+$")) 
         {
             if (Character.isLowerCase(input))
             {
                System.out.println("lower");
             } 
             else
             { 
                 System.out.println("upper");
             }
         }
         else if (input.matches("^(0|[1-9][0-9]*)$"))
         {
             System.out.println("digit");
         }
         else
         {
             System.out.println("other");
         }
    }
}

What are the errors? The more information you give, the better and faster we can all help you. — ajp15243, Nov 26 '13 at 15:26
You can't invoke a method `matches()` on a primitive type like char since it is not an object. — René Link, Nov 26 '13 at 15:27

Masudul · Answer 1 · 2013-11-26T15:35:19.357

3

Change the type of input

String input;// Change char to String 

if (input.matches("[a-zA-Z]+")) // Remove ^ and $
                              // String.matches don't need symbol ^ $

To test char you don't need String#matches,

  char input=' ';

    if (Character.isLowerCase(input) || Character.isUpperCase(input)) {
        if (Character.isLowerCase(input)) {
            System.out.println("lower");
        } else {
            System.out.println("upper");
        }
    } else if (Character.isDigit(input)) {
        System.out.println("digit");
    } else {
        System.out.println("other");
    }

edited Nov 26 '13 at 15:35

answered Nov 26 '13 at 15:26

Masudul

21,823
5
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Error: The method isLowerCase(char) in the type Character is not applicable for the arguments (String) – John Mark Saad Nov 26 '13 at 15:29
@JohnMarkSaad Just do `Character.isLowerCase(input.charAt(0))`. – René Jensen Nov 26 '13 at 15:31
@JohnMarkSaad, What do you want to test? If you want to test char than why matches? – Masudul Nov 26 '13 at 15:32

Manuel Manhart · Accepted Answer · 2013-11-26T15:39:42.507

0

Try:

for (String arg : args) {
    if (arg.matches("^[A-Z]+$")) {
        System.out.println("uppercase");
    } else if (arg.matches("^[a-z]+$")) {
        System.out.println("lowercase");
    } else if (arg.matches("^[0-9]+$")) {
        System.out.println("digits");
    } else {
        System.out.println("other");
    }
}

edited Nov 26 '13 at 15:39

answered Nov 26 '13 at 15:29

Manuel Manhart

4,819
3
24
28

edited and corrected it - I guess you want to parse all program arguments. – Manuel Manhart Nov 26 '13 at 15:34
Just run my code and if this is what you wanted mark this as the correct answer. If you want something different please be more specific what you need. – Manuel Manhart Nov 26 '13 at 15:41
1

thank you brother, you got a point. got some other error, but, i'll try to figure it now. (easy errors) – John Mark Saad Nov 26 '13 at 15:47

score 0 · Answer 3 · answered Nov 26 '13 at 15:37

If your input is in fact one character then you don't need regex but just set of few tests.

char input = 'z';// example character

if (Character.isLowerCase(input)) {
    System.out.println("lower");
} else if (Character.isUpperCase(input)) {
    System.out.println("upper");
} else if (Character.isDigit(input)) {
    System.out.println("digit");
} else {
    System.out.println("something is not right :/");
}

score 0 · Answer 4 · answered Nov 26 '13 at 15:39

Regex groups solution:

Pattern p = Pattern.compile("([a-z])|([A-Z])|([\\d])");
Matcher m = p.matcher("" + x);
m.matches();
if (m.group(1)!=null)
{
  System.out.println("lower");
} 
else if (m.group(2)!=null)
{ 
  System.out.println("upper");
}  
else if (m.group(3)!=null)
{ 
  System.out.println("digit");
} else
{ 
  System.out.println("other");
}

score 0 · Answer 5 · answered Nov 26 '13 at 15:51

you can convert String to char array, and then individual char with ascii value as below:-


public class CharsTester {


    public static void main(String[] args) {


        String input="ASD123asd_-";
        char temp[]=input.toCharArray();
        for (int i=0;i<temp.length;i++)
        {
            if(temp[i] >47 && temp[i]<58)
            {
                System.out.println(temp[i]+": is digit");
            }
            else if(temp[i] >64 && temp[i]<91)
            {
                System.out.println(temp[i]+": is CAPS char");
            }
            else if(temp[i] >96 && temp[i]<123)
            {
                System.out.println(temp[i]+": is small char");
            }
            else
                System.out.println(temp[i]+"is symbol or spetial char");

        }

    }
}

Char Tester in java (uppercase A-Z,lowercase a-z,digit 0-9,other)

5 Answers5