import java.util.Scanner;

/**

* Demonstrates uses of strings.

*/

public class Strings {

public static void main(String[] args) {

// Characters

String fruit = "banana";

char letter0 = fruit.charAt(0);

if (letter0 == 'A') {

System.out.println("It's an A!");

}

System.out.print("Roman alphabet: ");

for (char c = 'A'; c <= 'Z'; c++) {

System.out.print(c);

}

System.out.println();

System.out.print("Greek alphabet: ");

for (int i = 913; i <= 937; i++) {

System.out.print((char) i);

}

System.out.println();

// Which loop to use

Scanner in = new Scanner(System.in);

System.out.print("Enter a number: ");

while (!in.hasNextDouble()) {

String word = in.next();

System.err.println(word + " is not a number");

System.out.print("Enter a number: ");

}

double number = in.nextDouble();

in.nextLine(); // read the newline

// String iteration

for (int i = 0; i < fruit.length(); i++) {

char letter = fruit.charAt(i);

System.out.println(letter);

}

int length = fruit.length();

char last = fruit.charAt(length - 1); // correct

System.out.println(reverse(fruit));

// The indexOf method

int index = fruit.indexOf('a');

int index2 = fruit.indexOf('a', 2);

// Substrings

System.out.println(fruit.substring(0, 3));

System.out.println(fruit.substring(2, 5));

System.out.println(fruit.substring(6, 6));

System.out.println(fruit.substring(0));

System.out.println(fruit.substring(2));

System.out.println(fruit.substring(6));

// String comparison

System.out.print("Play again? ");

String answer = in.nextLine();

if (answer == "yes") { // wrong!

System.out.println("Let's go!");

} else {

System.out.println("Goodbye!");

}

if (answer.equals("yes")) { // correct

System.out.println("Let's go!");

}

String name1 = "Alan Turing";

String name2 = "Ada Lovelace";

if (name1.equals(name2)) {

System.out.println("The names are the same.");

}

int diff = name1.compareTo(name2);

if (diff < 0) {

System.out.println("name1 comes before name2.");

} else if (diff > 0) {

System.out.println("name2 comes before name1.");

} else {

System.out.println("The names are the same.");

}

}

/**

* Reverses a string, returns a new String.

*/

public static String reverse(String s) {

String r = "";

for (int i = s.length() - 1; i >= 0; i--) {

r = r + s.charAt(i);

}

return r;

}

}