For Tutorial

You can use the for loop to make a section of code repeat many times.

Program Code	Output
for (int i=0;i<10;i++) System.out.println(i);	0 1 2 3 4 5 6 7 8 9

The line System.out.println(i); happens 10 times.

There are four parts to the structure:

Initialization happens once at the start of the loop

int i=0;

Test - the loop executes only if the test is passed. The loop will complete when i reaches the value 10.

i<10

Iteration - this happens after each step. In this case i++ means increase i by one.

i++

Body - this is the bit that gets executed each time, the body is alway indented

System.out.println(i);

Putting it together the loop says:

Start by setting i to 0

Print the value i

increase i - from 0 to 1

Print i

increase i - now i is 2

Print i

increase i - now i is 3

Print i

increase i - now i is 4

Print i

increase i - now i is 5

Print i

increase i - now i is 6

Print i

increase i - now i is 7

Print i

increase i - now i is 8

Print i

increase i - now i is 9

Print i

increase i - now i is now 10, it fails the test i<10 and so the loop halts.

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