Enhanced for Loop

for (dataType element : array) {
    // use element — it holds the current value
}

int[] scores = {90, 85, 77, 92, 88};

for (int score : scores) {
    System.out.println(score);
}

90
85
77
92
88

// Enhanced for loop
for (int score : scores) {
    System.out.println(score);
}

// Is equivalent to this standard for loop:
for (int i = 0; i < scores.length; i++) {
    int score = scores[i];  // copy into local variable
    System.out.println(score);
}

int[] nums = {10, 20, 30, 40, 50};
int sum = 0;

for (int n : nums) {
    sum += n;
}
System.out.println("Sum: " + sum);  // 150

int[] values = {34, 67, 23, 89, 45};
int max = values[0];

for (int val : values) {
    if (val > max) {
        max = val;
    }
}
System.out.println("Max: " + max);  // 89

int[] grades = {95, 82, 91, 78, 96, 88};
int countA = 0;

for (int g : grades) {
    if (g >= 90) {
        countA++;
    }
}
System.out.println("A grades: " + countA);  // 3

String[] names = {"Alice", "Bob", "Charlie"};

for (String name : names) {
    System.out.println("Hello, " + name + "!");
}

int[] nums = {1, 2, 3, 4, 5};

for (int n : nums) {
    n = n * 2;  // only changes the local copy!
}

// Array is UNCHANGED
for (int n : nums) {
    System.out.print(n + " ");  // 1 2 3 4 5
}

for (int i = 0; i < nums.length; i++) {
    nums[i] = nums[i] * 2;  // this changes the actual array
}
// Now: 2 4 6 8 10

// If Student has a setGrade method:
Student[] students = { ... };

for (Student s : students) {
    s.setGrade(100);  // this DOES modify the actual Student objects
}

for (Student s : students) {
    s = new Student("New");  // only changes local copy — array unchanged
}

// Need index to modify elements
for (int i = 0; i < arr.length; i++) {
    arr[i] = arr[i] * 2;
}

// Need to go backward
for (int i = arr.length - 1; i >= 0; i--) {
    System.out.println(arr[i]);
}

// Need to compare adjacent elements
for (int i = 0; i < arr.length - 1; i++) {
    if (arr[i] == arr[i + 1]) {
        System.out.println("Duplicate found!");
    }
}

// Need to access a specific index
for (int i = 0; i < arr.length; i += 2) {
    System.out.println("Even index: " + arr[i]);
}

public class GradeReport {
    public static void main(String[] args) {
        int[] scores = {92, 85, 78, 95, 88, 67, 91};
        
        // Calculate average (enhanced for — just reading)
        int total = 0;
        for (int s : scores) {
            total += s;
        }
        double average = (double) total / scores.length;
        
        // Count above average
        int aboveAvg = 0;
        for (int s : scores) {
            if (s > average) {
                aboveAvg++;
            }
        }
        
        System.out.println("Average: " + average);       // 85.14...
        System.out.println("Above average: " + aboveAvg); // 4
        
        // Build pass/fail labels (need index — use standard for)
        String[] labels = new String[scores.length];
        for (int i = 0; i < scores.length; i++) {
            labels[i] = scores[i] >= 70 ? "Pass" : "Fail";
        }
    }
}