将值加x最简单的方法是什么

Question

I have a for loop with length 20.

I have a height of 800. I want to put a value 20 times separated by the same gap.

For example:

800 / 20 = 40

Every 40 I want to println the value. 40, 80, 120, 160... until 800.

I don't understand how to do this inside a loop. My approach is wrong and does not have the same gap between them.

for (int i = 0; i < array.size(); i++) {

   int posY = (i != 0) ? 800/ i : 800;
   println(posY);
}

Answer 1

you can use de Modulo Operador. more info

if(i % 40 == 0){
    println(posY);
}

Math Explanation of Modulo here

Answer 2

Well there are imho three different aproaches. Which one depends on what else you need to do with i.

1) Use i directly:

for (int i = 40; i <= 800; i+=40) {
    println(i);
}

This asumes that you don't need nothing else but the 20 numbers.

2) you need to count:

for (int i = 1; i <= 20; i++){
    println(i*40);
}

2b) application eg. if 800 is in a variable:

for (int i = 1; i <= 800/40; i++){
    println(i*40);
}

This assumes you need to track which step you are taking and want to do something with i.

3) you need the steps inbetween for something

 for (int i = 1; i <= 800; i++) {
     if(0 == i%40 ){ //if the rest of i/40 gives 0
         println(i);
     }
 }

This last version prints the same numbers but still i goes over all values inbetween.

Plus if you have an array you need to iterate over: replace the 800 with "array.length -1"
OR replace the "<=" by "<" and use "array.length" above.

(And well there are a whole lot of variations of this)