Question

How to check if a string is a positive number, negative number or not a number in Java

Answer 1

public class MyClass {
    public static String posOrNeg(String s) {
        try {
            double n = Double.parseDouble(s);
            if (n < 0)
               return "negative";
            else
               return "positive";
        } catch (NumberFormatException e) {
            return "not a number";
        }
    }
     
    public static void main(String args[]) {
        String s = "84593";
        System.out.println(posOrNeg(s));
 
        s = "-12";
        System.out.println(posOrNeg(s));
         
        s = "12W";
        System.out.println(posOrNeg(s));
    }
}
 
 
 
/*
run:
 
positive
negative
not a number
 
*/

 

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