Java String Examples

Check if string contains valid number example

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  • my question is how to find out largest number in string input {10 20 30} o/p- is 30.
    please give me a examples on that

    • import*;
      import java.util.*;
      class largest
      public static void main(String[] args)
      int large=0,a;
      Scanner in=new Scanner(;
      System.out.println(“Enter the input and type zero”0″ to end”);
      int a=in.nextInt();
      System.out.println(“The largest number is”+large);

  • 17. if( str[i].indexOf(“.”) > 0 )
    i have a doubt about this line of code.
    if i will take an string as “.20”, will it work ?. Because index of “.” here is equal to 0.
    So it will show the output as .20 is not a valid integer number.

  • Isn’t this a better version
    public class CheckNumber {

    public static void main(String[] args) throws IOException {
    System.out.println(“Enter a valid number:”);
    BufferedReader br = new BufferedReader(new InputStreamReader(;
    String input = br.readLine();
    try {
    Double numD = Double.parseDouble(input);
    System.out.println(numD + ” is a valid number.”);
    } catch (NumberFormatException nme) {
    // TODO Auto-generated catch block
    System.out.println(input + ” is not a valid number.”);


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