• An Iterator is an object that can be used to loop through collections, like ArrayList and HashSet.
  • It is called an "iterator" because "iterating" is the technical term for looping. To use an Iterator, you must import it from the java.util package.
  • for, while, ect
  • sequence of instructions or code being repeated until a specific end result is achieved
  • MacroMonkeys repo with caesar cipher shifts
  • Iteration is crucial to making coding simpler and less convoluted
  • Exam weights Iteration as 17.5-22.5% of the test, with 7-9 MC and part of FRQ 1

Nested Loop

  • nested for loop places one for loop inside another for loop
  • inner loop repeats for every iteration of the outer one

While Loop

  • repeats a specific block of code for as long until a certain condition is met, then it stops
  • do while loop - executes code at least once and then repeatedly depending on a boolean condition at the end of a block
int i = 5450000;
int years = 0;
while (i < 30000000){ //hack 2 with while loop
    i *= 1.05;
    years += 1;
}
System.out.println(years);

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FOR LOOPS

  • the test condition is checked each time through the loop and the loop continues as long as the condition is true
  • the loop control variable change is done at the end of each execution of the body of the loop
  • When the loop condition is false, execution will continue at the next statement after the body of the loop.
public class ForLoops { //hack 2
 
    public static void main(String[] args) {
        for (int x = 10; x <= 15; x++) { //for loop iteration
            System.out.println(x);
        }
    }
}
ForLoops.main(null);

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HW - Caesar Cipher 

public class CaesarCipher {

    String[] letters = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j",  //creates a string list for lowercase letters
    "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"};
    String[] capitalLetters = {"A", "B", "C", "D", "E", "F", "G", "H", "I", //uppercase
    "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"};
    
    static String message1 = "Kfzb gly!"; 
    static String message2 = "zlab zlab zlab";
    static String message3 = "prmbozxifcoxdfifpqfzbumfxifalzflrp"; //sets 3 different messages

    String letterIndividual = "";


    public CaesarCipher(String msg) {
        for (int i = 0; i < msg.length(); i++) {
            letterIndividual = msg.substring(i, i+1);
            //iteration through i++ and j++

            if (letterIndividual.equals(" ")) {
                System.out.print(" "); 
            } //if statement 

            if (letterIndividual.equals("!")) {
                System.out.print("!"); 
            }

            for (int j = 0; j < letters.length; j++) {
                if (letterIndividual.equals(letters[j])) {
                    System.out.print(letters[(j+3)%26]); 
                } //adds three and then uses modulus function

                if (letterIndividual.equals(capitalLetters[j])) {
                    System.out.print(capitalLetters[(j+3)%26]); //key shift
                }
            
            }
        }
        System.out.println(""); 
    }

    public static void main(String[] args) { //prints the decoded messages
        CaesarCipher decode = new CaesarCipher(message1); 
        CaesarCipher decode2 = new CaesarCipher(message2); 
        CaesarCipher decode3 = new CaesarCipher(message3); 

    }
}
CaesarCipher.main(null)

Nice job!
code code code
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