3.7.1 - E6.4 - How to find uppercase letters or vowels in a string?

import java.util.Scanner;

class stuff {

public static void main(String[] args) {

Scanner Riley = new Scanner(System.in);

System.out.println("Please enter a string:");

String s = Riley.nextLine();

String S = "";

for (int i=1; i<=s.length(); i++)

if (s.substring(i-1,i).toUpperCase().equals(s.substring(i-1,i))) {

S = S + s.substring(i-1,i);

}

System.out.println(S);

System.out.println("Please enter a string:");

String t = Riley.nextLine();

String T = "";

for (int i=1; i<=t.length()-1; i+=2) {

T = T + t.substring(i,i+1);

}

System.out.println(T);

System.out.println("Please enter a string:");

String u = Riley.nextLine();

for (int i=0; i<=u.length()-1; i++) {

switch (u.substring(i,i+1)) {

case "a": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

case "e": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

case "i": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

case "o": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

case "u": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

case "A": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

case "E": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

case "I": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

case "O": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

case "U": u = u.substring(0,i) + "_" + u.substring(i+1,u.length()); break;

default: break;

}

}

System.out.println(u);

System.out.println("Please enter a string:");

String v = Riley.nextLine();

int V = 0;

for (int i=0; i<=v.length()-1; i++) {

switch (v.substring(i,i+1)) {

case "a": V++; break;

case "e": V++; break;

case "i": V++; break;

case "o": V++; break;

case "u": V++; break;

case "A": V++; break;

case "E": V++; break;

case "I": V++; break;

case "O": V++; break;

case "U": V++; break;

default: break;

}

}

System.out.println("The number of vowels in your string is " + V);

System.out.println("Please enter a string:");

String w = Riley.nextLine();

for (int i=0; i<=w.length()-1; i++) {

switch (w.substring(i,i+1)) {

case "a": System.out.println("The posistion of letter a is " + (i+1)); break;

case "e": System.out.println("The posistion of letter e is " + (i+1)); break;

case "i": System.out.println("The posistion of letter i is " + (i+1)); break;

case "o": System.out.println("The posistion of letter o is " + (i+1)); break;

case "u": System.out.println("The posistion of letter u is " + (i+1)); break;

case "A": System.out.println("The posistion of letter A is " + (i+1)); break;

case "E": System.out.println("The posistion of letter E is " + (i+1)); break;

case "I": System.out.println("The posistion of letter I is " + (i+1)); break;

case "O": System.out.println("The posistion of letter O is " + (i+1)); break;

case "U": System.out.println("The posistion of letter U is " + (i+1)); break;

default: break;

}

}

}

}