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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.