How do I return a number between 0 and 4, depending the input number?
For example if I pass it number 23 it will return 3. The number set should look like
0 5 10 15 20 ..
1 6 11 16 21 ..
2 7 12 17 22 ..
3 8 13 18 23 ..
4 9 14 19 24
What's the math for this?
Use the modulo operation, typically % in many languages (and mod in many others).
10 % 5 = 0
17 % 3 = 2
The above two answers are correct, the Modulo operator is very useful in calculating remainders. For example the "pass 23 return 3" : 23 % 5 works as follows: 5 goes into 23 4 times ( (int) 23 / 5 = 4) the modulo operater then gives you the remainder (23 - (5 * 4)), which happens to be the number you and your assignment are looking for, 3.