for loops

Counting loops are so common that Java has a shorter way to write them. The for loop puts all three parts on one line, separated by semicolons:

for (int i = 1; i <= 5; i++) {
    System.out.println(i);
}

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for (start; condition; change) does the same as this while loop:

int i = 1;
while (i <= 5) {
    System.out.println(i);
    i++;
}

• The start runs once, before the first round.
• The condition is checked before every round.
• The change runs at the end of every round.

A loop variable is often called i. Made in the for line, it only exists inside the loop. Counting down and other steps work too: for (int i = 10; i >= 1; i--) counts from 10 to 1, and i += 2 instead of i++ takes every second number.