/** the Strings class introduces us to the data type used for text. */
/* def of a string is a sequence of characters */
import java.util.Scanner;

public class Strings {
  public static void main(String[] args) {
    String name1 = "John Doe";
    System.out.println("name1 is " +  name1);
    String name2 = "Alice";
    System.out.println("name2 is " +  name2);
    if (name1.length() != name2.length())
      System.out.println("length of name2 is: " + name2.length());
    System.out.println("name2's first initial is: " + name2.charAt(0));
    int i;
    Scanner sc = new Scanner(System.in);
    System.out.print("enter an index: ");
    i = sc.nextInt();
    sc.nextLine(); // skip newline
    if (i >= 0 && i<name2.length())
        System.out.println("name2's char at " + i + " is: " + name2.charAt(i));
    name2 = name1;
    System.out.println("name2 is now " +  name2);
    if (name1 == name2)
      System.out.println("name1 and name2 are equal");
    
    System.out.print("Enter a name: ");
    String name3 = sc.nextLine();
    /* Comparison of references compares addresses, so the following will
     * be false
     */
    if (name3==name2)
      System.out.println("name3 and name2 are equal");
    /* however, the .equals method of the string class compares the actual
     * character sequence.
     */
    if (name3.equals(name2))
      System.out.println("name3 and name2 have the same sequence of chars.");
    
    System.out.println("name2 in uppercase is: " + name2.toUpperCase()
                         + " name2 remains: " + name2);
   }
}    
/** Lab 15:
  * Write a java class called DNA that reads in a sequence that represents 
  * DNA.
  * Iterate through the input string and print whether it contains any
  * characters that do not represent a valid base (A, G, C, T).
  */