java - Incremental Math Trouble -

i've been perplexed how write math small game i'm creating. game own personal journey learning more java , largely based off of monolith, http://monolith.greenpixel.ca/. i've looked @ source code game can't ascertain how developer math.

here code have far.

package damagedealer; import javax.swing.*; import java.awt.*; import java.awt.gridbaglayout; import java.awt.event.actionevent; import java.awt.event.actionlistener;  public class take1 {      int dmg = 0;     int epoints = 1000;     int intunit1 = 0;      public static void main(string[] args) {         new take1();     }      public take1() {         javax.swing.swingutilities.invokelater(new runnable() {             @override             public void run() {                 try {                     uimanager.setlookandfeel(uimanager.getsystemlookandfeelclassname()); }                 catch (unsupportedlookandfeelexception ex) {                     ex.printstacktrace(); }                 catch (illegalaccessexception ex) {                     ex.printstacktrace(); }                 catch (instantiationexception ex) {                     ex.printstacktrace(); }                 catch (classnotfoundexception ex) {                     ex.printstacktrace(); }                  jframe frame = new jframe("button clicker");                 frame.setdefaultcloseoperation(jframe.exit_on_close);                 frame.getcontentpane().add(new addcomponentstopane());                    frame.setsize(300, 500);                 frame.setlocationrelativeto(null);                 frame.setvisible(true);                 frame.setresizable(false);             }         });     }         protected class addcomponentstopane extends jpanel {           /**          *           */         private static final long serialversionuid = 1l;          public addcomponentstopane() {             jpanel apppanel = new jpanel(new gridbaglayout());             gridbagconstraints gbc = new gridbagconstraints();                          gbc.fill = gridbagconstraints.horizontal;             gbc.anchor = gridbagconstraints.center;             gbc.insets = new insets(5, 5, 5, 5);              jlabel evopoints = new jlabel();             evopoints.settext("points: " + string.valueof(epoints));             gbc.gridx = 1;             gbc.gridy = 0;             apppanel.add(evopoints, gbc);              jbutton jbtunit1 = new jbutton("unit 1");             gbc.gridx = 0;             gbc.gridy = 1;             apppanel.add(jbtunit1, gbc);              jlabel lblunit1 = new jlabel();             lblunit1.settext(string.valueof(intunit1));             gbc.gridx = 1;             gbc.gridy = 1;             apppanel.add(lblunit1, gbc);              jbutton jbtdamage = new jbutton("damage");                                   gbc.gridx = 0;             gbc.gridy = 10;             apppanel.add(jbtdamage, gbc);              jlabel damageoutput = new jlabel();             damageoutput.settext(string.valueof(dmg));             gbc.gridx = 1;             gbc.gridy = 10;             apppanel.add(damageoutput, gbc);              add(apppanel, gbc);              jbtdamage.addactionlistener(new actionlistener() {                 public void actionperformed(actionevent e) {                     dmg++;                     damageoutput.settext(string.valueof(dmg));                     if ((dmg % 10) == 0) {                         epoints++;                         evopoints.settext("points: " + string.valueof(epoints));                     }                  }             });              jbtunit1.addactionlistener(new actionlistener() {                 public void actionperformed(actionevent e) {                     if (epoints >= 10) {                         intunit1++;                         epoints = epoints - 10;                         lblunit1.settext(string.valueof(intunit1));                         evopoints.settext("points: " + string.valueof(epoints));                     }                 }             });         }               } } 

right now, have 2 buttons, jbtunit1 , jbtdamage. , respective action listeners @ bottom.

the math have works if dmg value evenly divisible ten. @ point (when dmg divisible 10), epoints value incremented. however, jbtunit1 supposed increment dmg output additional point each unit. therefore, (dmg % 10) == 0 won't work because surpass values multiple times before reaching exact %10.

question: how should math? or better yet: better (or preferred) method doing type of math?

thanks help! mikey

try replacing this:

dmg++; damageoutput.settext(string.valueof(dmg)); if ((dmg % 10) == 0) {     epoints++;     evopoints.settext("points: " + string.valueof(epoints)); } 

with this:

dmg+= 1+intunit1; //deal more damage more units damageoutput.settext(string.valueof(dmg)); int newepoints = dmg/10 - spentepoints; if(epoints != newepoints) {     evopoints.settext("points: " + string.valueof(newepoints)); } epoints = newepoints; 

then add spentepoints field in main class keep track of amount spent , instead of substracting epoints counter every time buy units, add spent amount spentepoints counter.

note games these tend escalate numbers , integer type variables overflow. take biginteger class lets have almost infinitely large numbers.