Arrays and Loops

Arrays and Loops

The real power of an array shows up when you process every element. The classic partner is a for loop.

The classic pattern

string cars[4] = {"Volvo", "BMW", "Ford", "Mazda"};

for (int i = 0; i < 4; i++) {
    cout << cars[i] << "\n";
}

• i starts at 0 and keeps going while i < 4.
• The loop visits indexes 0, 1, 2, and 3 - exactly the valid ones.

Why i < 4 and not i <= 4?

The array has 4 elements, so its legal indexes are 0 through 3. The condition i < 4 stops right at 4. If you wrote i <= 4, the loop would be trying to read cars[4], which doesn't exist.

Range-based loop (the easy way)

When you don't need the index, a range-based loop is simpler and safer:

for (string car : cars) {
    cout << car << "\n";
}

It hands you each element in order, with no counting bookkeeping at all.

TL;DR

• Loop over an array with a for loop.
• Use i < arraySize so the loop stays inside the valid indexes.
• cars[i] pulls the element at index i.
• A range-based loop for (element : array) visits every element without an index.
• Keep the loop within the array bounds.