String Methods

Objectives

1. Discuss string methods.

Notes

• String methods
  • + will add two strings. (Concatenation)
  • There are many string methods
  • We care about
    • bool: .equals(string)
    • bool: .equalsIgnoreCase(string)
    • bool: .startsWith(string)
    • bool: .endsWith(string)
    • int: .compareTo(string) (negative, 0, positive)
    • int: .compareToIgnoreCase(string) (negative, 0, positive)
    • char: .charAt(int)
    • int: .length()
    • string: substring(begin, end) end is optional
    • string: .toLowerCase()
    • string: .toUpperCase()
    • int: .indexOf(string), -1 on fail
• The Code

  import java.util.Scanner;
  
  public class StringDemo {
      public static void main(String[] args) {
          String  word = "hello";
          System.out.printf("%s is the word\n",word);
  
          String phrase = "";
  
          Scanner myScanner = new Scanner(System.in);
  
          while (!phrase.equalsIgnoreCase("quit")) {
              System.out.print("Enter a phrase = >");
              phrase = myScanner.nextLine();
              System.out.printf("The scanner got '%s'\n",phrase);
              System.out.printf("That is %d letters long.\n", phrase.length());
              System.out.printf("As upper case: '%s'\n", phrase.toUpperCase());
              System.out.printf("But Phrase did not change: '%s'\n",phrase);
              System.out.printf("As lower case: '%s'\n", phrase.toLowerCase());
  
              if (phrase.length() > 3) {
                 int middle = phrase.length()/2;
                 String middleLetters = phrase.substring(middle-1, middle+2);
                 System.out.printf("The middle of the string is '%s'\n",middleLetters);
              }
  
              System.out.println();
  
              int i = 0;
              while(i < phrase.length()){
                 System.out.printf("%c is at %d\n",phrase.charAt(i), i);
                 ++i;
              }
  
              System.out.println();
          }
      }
  }