Finding all uppercase letters of a string in java

Question

So I\'m trying to find all the uppercase letters in a string put in by the user but I keep getting this runtime error:

Exception in thread \"main\" java.lan         


        

Answer 1

Try this...

Method:

public int findUpperChar(String valitateStr) {
    for (int i = valitateStr.length() - 1; i >= 0; i--) {
        if (Character.isUpperCase(valitateStr.charAt(i))) {
            return i;
        }
    }
    return -1;
}

Usage:

String passwordStr = password.getText().toString();

 .......

int len = findUpperChar(passwordStr);

if ( len != -1) {

      capitals exist.   

  } else {

      no capitals exist.            
}

Answer 2

You can increase the readability of your code and benefit from some other features of modern Java here. Please use the Stream approach for solving this problem. Also, I suggest importing the least number of libraries into your class. Please avoid using .* while importing.

import java.util.Scanner;

public class P43 {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Please give a string: ");
        String x = in.next();
        x.chars().filter(c -> Character.isUpperCase(c))
                .forEach(c -> System.out.print((char) c + " "));
    }
}

Sample input:

saveChangesInTheEditor

Sample output:

C I T E

Answer 3

The array index out of bounds is due to the for loop not terminating on length - 1, it is terminating on length Most iterating for loops should be in the form:

for (int i = 0; i < array.length; i++) {
    // access array[i];
}

It's the same with a string.

Perhaps a cleaner way would be:

String inputString; // get user input

String outputString = "";

for (int i = 0; i < inputString.length; i++) {
    c = inputString.charAt(i);
    outputString += Character.isUpperCase(c) ? c + " " : ""; 
}
System.out.println(outputString);

Edit: Forgot String Doesn't implement Iterable<Character>, silly Java.

Answer 4

The simplest way I know is to use regex replacement.

isUp = x.replaceAll("[^A-Z]", "");

In simple terms, this uses a regular expression which matches any character which is not in the A-Z range, and replaces it with an empty string.

Answer 5

import java.util.Scanner;
class Demo
{
    public static void main(String[] args)
    {
         StringBuilder s=new StringBuilder();
         Scanner input = new Scanner(System.in);
         System.out.println("Enter your String");
         String str= input.nextLine();

         for(int i=0; i<str.length(); i++)
         {
            if(Character.isUpperCase(str.charAt(i)))
            {
               System.out.print(str.charAt(i)+" ");
            }
         }
      }
}

Answer 6

public class Cama {

public static void main(String[] args) {
    String camal = "getStudentByName";
    String temp = "";
    for (int i = 0; i < camal.length(); i++) {
        if (Character.isUpperCase(camal.charAt(i))) {
            System.out.print(" " + Character.toLowerCase(camal.charAt(i)));
        } else if (i == 0) {
            System.out.print(Character.toUpperCase(camal.charAt(i)));
        }else{
            System.out.print(camal.charAt(i));
        }
    }
}
}