Unit 6.3 Lesson

• Enhanced For Loop (For-each)
  • Pros
  • Cons
• Regular For Loop
• Enhanced For Loop
• Comparing a regular for loop with the enhanced for loop
• Hacks

Final Hack

Enhanced For Loop (For-each)

An enhanced For Loop is a simplified version of a regular for loop, where the coder doesn’t need to specify the increment and can access each element directly.

Pros

• Can access the elements of a array instad of a counter
• Enhanced readability
• Less likely to be buggy

Cons

• Can only traverse the array in order
• Accesses a copy of the array, so modifications to the variables are not saved in the original array

Regular For Loop

Enhanced For Loop

int[] numbers = {10, 20, 30, 40, 50};
for (int number : numbers) {
    number += 1;
    System.out.println(number);
};

System.out.println(Arrays.toString(numbers))

Comparing a regular for loop with the enhanced for loop

Popcorn Hack: Rewrite this code to use an enhanced for loop instead. make comments explaining what you added/changed

String[] languages = {"Java", "Python", "Markdown", "C++", "Go", "JavaScript", "HTML"};

for (int i = 0; i<languages.length; i++) {
    System.out.println(languages[i]);
};

Hacks

1. Build the loop
2. Multiple Choice
3. Find each index of the letter ‘a’ in each word
4. Find the error
5. HW Hack

String[] myArray = {'Add an array here'};

// Add a loop to go through the array here

private String[] myArray = {
    "And", "Table", "Shirts", "Tea", "School Day"
};

for (String currentWord : myArray) {
    // Add code here
}

A: System.out.println(myArray.currentWord.length());
B: System.out.println(myArray[index].length());
C: System.out.println(myArray[currentWord].length());
D: System.out.println(currentWord.length());

String[] fruits = {"Apple", "Banana", "Orange"};

for (String fruit: fruits) {
    // Find the index of the letter 'a' in each fruit
};

String[] myArray = {"Object 1", "Object 2", "Object 3", "Object 4", "Object 5"};

for (currentWord: myArray) {
    System.out(currentWord)
};

// There are 3 errors, can you find them?

Final Hack

Add to the code below to create a average grade calculator (using an enhanced for loop)

Integer[] grades = {88, 93, 55, 68, 77};

Scanner userGrades = new Scanner(System.in);
System.out.print("Enter a grade: ");
int grade = Integer.parseInt(userGrades.nextLine());

// Add code here to take the average

grades = Arrays.copyOf(grades, grades.length + 1);
grades[grades.length - 1] = grade;
System.out.println(Arrays.toString(grades));