class - Java - Costum Classes, code not working -

for reason when run file answer seems 0. i'm still new java explain me i've done wrong.. seems fine me.

public class bus { public static void main(string[] args) {     bus fivepm = new bus(23, 120);     bus elevenam = new bus(27, 140);      system.out.println(fivepm.gallonsused());     system.out.println(elevenam.gallonsused()); } private int mpg; private int milestravelled; private double used;  public bus(int mpg, int milestravelled){      this.mpg = mpg;      this.milestravelled = milestravelled;  } public double gallonsused(){     this.used = this.mpg/this.milestravelled;     return this.used;  } } 

in both of instantiated bus objects, milestravelled less mpg.

when divide int int, int.

this.mpg/this.milestravelled; 

this return 0 because digits after decimal point don't matter if it's int.

to make them not ints, things like:

this.mpg * 1.0 / this.milestravelled 

or

this.mpg/((double) this.milestravelled)