Enhanced For Loops

List<String> customerNames = new List<String>{'Acme Corp', 'Globex', 'Initech'};

for (String customerName : customerNames) {
    System.debug('Welcome, ' + customerName);
}

1. List<String> customerNames = new List<String>{...}; — three names.
2. (blank line)
3. for (String customerName : customerNames) { — read as "for each String in customerNames, call it customerName." There's no counter to initialize, check, or increment — Apex handles walking through the list for you.
4. System.debug('Welcome, ' + customerName); — runs once per name, with customerName holding a different value each pass.
5. } — closes the loop.

List<Decimal> donationAmounts = new List<Decimal>{50, 250, 1000, 25};
Decimal totalRaised = 0;

for (Decimal amount : donationAmounts) {
    totalRaised += amount;
}

System.debug('Total raised: ' + totalRaised);

1. List<Decimal> donationAmounts = new List<Decimal>{50, 250, 1000, 25}; — four donations.
2. Decimal totalRaised = 0; — the running total, starting at zero.
3. (blank line)
4. for (Decimal amount : donationAmounts) { — one pass per donation amount.
5. totalRaised += amount; — adds this pass's amount to the running total.
6. } — closes the loop.
7. (blank line)
8. System.debug('Total raised: ' + totalRaised); — logs the final total, 1325, after all four amounts have been added.

Summing a batch of donations doesn't need index tracking at all — just "look at each amount, add it to the running total" — which is exactly what an enhanced for loop expresses.

An enhanced for loop never tells you which position you're at — there's no i to reference. If you need the index (say, to only process every other item, or to compare an item to the one before it), reach for the classic for loop from the previous lesson instead.