After some months of struggle (i must admit); working alone, i finally came up with a solution wich seems perfect till now. I am just surprised that i've not been able to find a mistake since months of tests.
I am almost convinced that what i have at least come very close to my goal if not already achieved.
So the purpose of this blog is to give you the opportunity to "validate" my work with additional tests.
All you will need to do is to copy and paste the code below and execute after compiling it in a suitable IDE for java (Dr java, Eclipse helios, etc.....).
This is the capture of the GUI after execution:
While executing, open the windows calculator in parallel and try all the operations you can on both calculators. My prediction is that you will always come up with the same outputs.
But if it ever happen that you find discrepencies in outputs, fill free to comments and i'll do my best to fix the problem.
HERE IS THE NON- OPTIMISED CODE(i am very sorry for the poor presentation):
import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
import java.awt.Component;
import javax.swing.border.Border;
import javax.swing.border.LineBorder;
import java.awt.event.*;
import java.awt.*;
import java.awt.Component;
import javax.swing.border.Border;
import javax.swing.border.LineBorder;
class calculator extends JFrame implements ActionListener
{
//graphical features' variables
private int toStoreFeatures=0;
JButton g=new JButton("g");
TextArea display = new TextArea( "", 1, 40, TextArea.SCROLLBARS_NONE );
private String[] buttonNames={"Backspace","CE","C","7","8","9","/","sqrt","4","5","6","*","%","1","2","3","-","1/x","0","+/-",",","+","="," M","MC","MR","MS","M+"};
private Component [] features=new Component[28];
private JPanel bReg1 = new JPanel();
private JPanel bReg2 = new JPanel();
private JPanel labelReg = new JPanel();
private JPanel buttonArea = new JPanel();
// variables to manage operations
private String textOnScreen="0";
private String memory="0";
private boolean validOp=false;
private boolean concDigit=false;//decides if the digit pressed by the user must be concatenate or simply replace the existing one
private String errorMessage;
private String currentOp=null;
private Operation proceedOp=null;//object wich will be created each time to proceed a new operation
private boolean Bakspace=true;
private boolean currCharIsCom=false;
private boolean isDouble=false;//tells if the number on screen is double(to check if it already has the comma)
calculator()
{
super("calculator");
bReg1.setLayout(new GridLayout(5,1,10,10));
bReg1.add(nextButtonGrid(1,3,10,10));
bReg1.add(nextButtonGrid(1,5,10,10));
bReg1.add(nextButtonGrid(1,5,10,10));
bReg1.add(nextButtonGrid(1,5,10,10));
bReg1.add(nextButtonGrid(1,5,10,10));
bReg2.setLayout(new GridLayout(5,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
buttonArea.setLayout(new BorderLayout(15,15));
buttonArea.add(bReg2, BorderLayout.WEST);
buttonArea.add(bReg1,BorderLayout.CENTER);
enrobComponent(buttonArea,true,true,true,true);
/**display.setOpaque(true);
display.setBackground(Color.white);
display.setBorder(new LineBorder(Color.gray)); */
display.setBackground( Color.WHITE);
display.setEditable( false );
labelReg.add(display);
setLayout(new BorderLayout());
add(enrobComponent(labelReg,true,true,false,true),BorderLayout.NORTH);
add(enrobComponent(buttonArea,true,true,true,true),BorderLayout.CENTER);
int i=0; while(i!=23){((JButton)features[i]).addActionListener(this);if(i==22){i=23;} if(i==27){i=22;}System.out.println("Still in! "+i);i++;}
manageMemory("MC");
manageErasers("CE");
pack();
setVisible(true);
}
//class operation dont les instances devront executer chaque nouvelle operation
public static class Operation{
public String param1;
public String param2;
public String currentOp;
public String percent;
public String lastOp;
private Operation(String par1,String op,String par2){
param1=par1; param2=par2; currentOp=op;percent=null; lastOp=null;//initialising the parameters of the object operation
}
private String eval(){
return param1;
}
private void replaceOp(String op){currentOp=op;}
}
public void actionPerformed(ActionEvent e) { boolean done=false;int k;//mettre une lettre commune devant les noms de tous les boutons ayant les memes methodes
//aurait rendu leur identification bien plus facile et plus generale; mais l'idee m'est venu apres cet implementation un peut compliquee
for(k=0;k<features.length&&!done;k++){if(e.getSource()==features[k]){done=true;k--;}}
String repere=buttonNames[k];
try{Double.parseDouble(textOnScreen);
try{ if(Integer.parseInt(repere)<10){manageDigits(repere);}}catch(NumberFormatException ex){ if(repere.charAt(0)=='M'){
manageMemory(repere);}else if(repere.charAt(0)=='B'||repere.charAt(0)=='C'){manageErasers(repere);}else if(repere.charAt(0)==','){
comma();}else if(repere.charAt(0)=='='){equal();}else if(repere.charAt(0)=='%'){percentage();}else if(repere.length()==1){proceedOp(repere);}else{
oneParamOp(repere);}}
}catch(RuntimeException r){if(repere.charAt(0)=='C'){textOnScreen="0";manageErasers(repere);}}
}
private JPanel nextButtonGrid(int lon, int larg, int hspace, int vspace){
JPanel toReturn=new JPanel(); int r=0,i;
toReturn.setLayout(new GridLayout(lon,larg,hspace,vspace));
for(i=0;i<lon*larg;i++)
{
r=i+toStoreFeatures;
if(r!=23)
{
features[r]=new JButton(buttonNames[r]);
}else{
JLabel lab=new JLabel(buttonNames[r]);
lab.setBorder(new LineBorder(Color.gray));
features[r]=lab;
}
toReturn.add(features[r]);
}
toStoreFeatures+=i;
return toReturn;
}
private JPanel enrobComponent(JPanel toEnrob,boolean enrobNorth,boolean enrobEast,boolean enrobSouth,boolean enrobWest){
JPanel toReturn=new JPanel(); toReturn.setLayout(new BorderLayout(10,10));
if(enrobNorth){
toReturn.add(new JLabel(),BorderLayout.NORTH);}
if(enrobEast){
toReturn.add(new JLabel(),BorderLayout.EAST); }
if(enrobSouth){
toReturn.add(new JLabel(),BorderLayout.SOUTH); }
if(enrobWest){
toReturn.add(new JLabel(),BorderLayout.WEST);
}
toReturn.add(toEnrob,BorderLayout.CENTER);
return toReturn;
}
private void oneParamOp(String op){//sqrt,1/x,+/-
if(op.equals("+/-")){
char c=' ';
for(int i=0; i<textOnScreen.length();i++){if(textOnScreen.charAt(i)=='E'){c='E';}}
if(c!='E'){
if(textOnScreen.charAt(0)=='-'){textOnScreen=textOnScreen.substring(1,textOnScreen.length());}else if(!textOnScreen.equals("0")){textOnScreen="-"+textOnScreen;}
}else{textOnScreen=eval(textOnScreen,op);}
affiche(textOnScreen);
}else{
textOnScreen=eval(textOnScreen,op);
affiche(textOnScreen);
}
if((proceedOp!=null)){
if(!("=".equals(proceedOp.lastOp)&&(op.equals("+/-")))){
proceedOp.param2=textOnScreen;
}
}
if(!(op.equals("+/-"))){concDigit=false;}
}
private void proceedOp(String op){//+,-,*,/
if(proceedOp==null){
replaceOp(op);
}else if(proceedOp.param2==null){
proceedOp.replaceOp(op);}else if(("=").equals(proceedOp.lastOp)){proceedOp=new Operation(textOnScreen,op,null);}else{
textOnScreen=eval(proceedOp.param1,proceedOp.currentOp,proceedOp.param2);
{
//graphical features' variables
private int toStoreFeatures=0;
JButton g=new JButton("g");
TextArea display = new TextArea( "", 1, 40, TextArea.SCROLLBARS_NONE );
private String[] buttonNames={"Backspace","CE","C","7","8","9","/","sqrt","4","5","6","*","%","1","2","3","-","1/x","0","+/-",",","+","="," M","MC","MR","MS","M+"};
private Component [] features=new Component[28];
private JPanel bReg1 = new JPanel();
private JPanel bReg2 = new JPanel();
private JPanel labelReg = new JPanel();
private JPanel buttonArea = new JPanel();
// variables to manage operations
private String textOnScreen="0";
private String memory="0";
private boolean validOp=false;
private boolean concDigit=false;//decides if the digit pressed by the user must be concatenate or simply replace the existing one
private String errorMessage;
private String currentOp=null;
private Operation proceedOp=null;//object wich will be created each time to proceed a new operation
private boolean Bakspace=true;
private boolean currCharIsCom=false;
private boolean isDouble=false;//tells if the number on screen is double(to check if it already has the comma)
calculator()
{
super("calculator");
bReg1.setLayout(new GridLayout(5,1,10,10));
bReg1.add(nextButtonGrid(1,3,10,10));
bReg1.add(nextButtonGrid(1,5,10,10));
bReg1.add(nextButtonGrid(1,5,10,10));
bReg1.add(nextButtonGrid(1,5,10,10));
bReg1.add(nextButtonGrid(1,5,10,10));
bReg2.setLayout(new GridLayout(5,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
bReg2.add(nextButtonGrid(1,1,10,10));
buttonArea.setLayout(new BorderLayout(15,15));
buttonArea.add(bReg2, BorderLayout.WEST);
buttonArea.add(bReg1,BorderLayout.CENTER);
enrobComponent(buttonArea,true,true,true,true);
/**display.setOpaque(true);
display.setBackground(Color.white);
display.setBorder(new LineBorder(Color.gray)); */
display.setBackground( Color.WHITE);
display.setEditable( false );
labelReg.add(display);
setLayout(new BorderLayout());
add(enrobComponent(labelReg,true,true,false,true),BorderLayout.NORTH);
add(enrobComponent(buttonArea,true,true,true,true),BorderLayout.CENTER);
int i=0; while(i!=23){((JButton)features[i]).addActionListener(this);if(i==22){i=23;} if(i==27){i=22;}System.out.println("Still in! "+i);i++;}
manageMemory("MC");
manageErasers("CE");
pack();
setVisible(true);
}
//class operation dont les instances devront executer chaque nouvelle operation
public static class Operation{
public String param1;
public String param2;
public String currentOp;
public String percent;
public String lastOp;
private Operation(String par1,String op,String par2){
param1=par1; param2=par2; currentOp=op;percent=null; lastOp=null;//initialising the parameters of the object operation
}
private String eval(){
return param1;
}
private void replaceOp(String op){currentOp=op;}
}
public void actionPerformed(ActionEvent e) { boolean done=false;int k;//mettre une lettre commune devant les noms de tous les boutons ayant les memes methodes
//aurait rendu leur identification bien plus facile et plus generale; mais l'idee m'est venu apres cet implementation un peut compliquee
for(k=0;k<features.length&&!done;k++){if(e.getSource()==features[k]){done=true;k--;}}
String repere=buttonNames[k];
try{Double.parseDouble(textOnScreen);
try{ if(Integer.parseInt(repere)<10){manageDigits(repere);}}catch(NumberFormatException ex){ if(repere.charAt(0)=='M'){
manageMemory(repere);}else if(repere.charAt(0)=='B'||repere.charAt(0)=='C'){manageErasers(repere);}else if(repere.charAt(0)==','){
comma();}else if(repere.charAt(0)=='='){equal();}else if(repere.charAt(0)=='%'){percentage();}else if(repere.length()==1){proceedOp(repere);}else{
oneParamOp(repere);}}
}catch(RuntimeException r){if(repere.charAt(0)=='C'){textOnScreen="0";manageErasers(repere);}}
}
private JPanel nextButtonGrid(int lon, int larg, int hspace, int vspace){
JPanel toReturn=new JPanel(); int r=0,i;
toReturn.setLayout(new GridLayout(lon,larg,hspace,vspace));
for(i=0;i<lon*larg;i++)
{
r=i+toStoreFeatures;
if(r!=23)
{
features[r]=new JButton(buttonNames[r]);
}else{
JLabel lab=new JLabel(buttonNames[r]);
lab.setBorder(new LineBorder(Color.gray));
features[r]=lab;
}
toReturn.add(features[r]);
}
toStoreFeatures+=i;
return toReturn;
}
private JPanel enrobComponent(JPanel toEnrob,boolean enrobNorth,boolean enrobEast,boolean enrobSouth,boolean enrobWest){
JPanel toReturn=new JPanel(); toReturn.setLayout(new BorderLayout(10,10));
if(enrobNorth){
toReturn.add(new JLabel(),BorderLayout.NORTH);}
if(enrobEast){
toReturn.add(new JLabel(),BorderLayout.EAST); }
if(enrobSouth){
toReturn.add(new JLabel(),BorderLayout.SOUTH); }
if(enrobWest){
toReturn.add(new JLabel(),BorderLayout.WEST);
}
toReturn.add(toEnrob,BorderLayout.CENTER);
return toReturn;
}
private void oneParamOp(String op){//sqrt,1/x,+/-
if(op.equals("+/-")){
char c=' ';
for(int i=0; i<textOnScreen.length();i++){if(textOnScreen.charAt(i)=='E'){c='E';}}
if(c!='E'){
if(textOnScreen.charAt(0)=='-'){textOnScreen=textOnScreen.substring(1,textOnScreen.length());}else if(!textOnScreen.equals("0")){textOnScreen="-"+textOnScreen;}
}else{textOnScreen=eval(textOnScreen,op);}
affiche(textOnScreen);
}else{
textOnScreen=eval(textOnScreen,op);
affiche(textOnScreen);
}
if((proceedOp!=null)){
if(!("=".equals(proceedOp.lastOp)&&(op.equals("+/-")))){
proceedOp.param2=textOnScreen;
}
}
if(!(op.equals("+/-"))){concDigit=false;}
}
private void proceedOp(String op){//+,-,*,/
if(proceedOp==null){
replaceOp(op);
}else if(proceedOp.param2==null){
proceedOp.replaceOp(op);}else if(("=").equals(proceedOp.lastOp)){proceedOp=new Operation(textOnScreen,op,null);}else{
textOnScreen=eval(proceedOp.param1,proceedOp.currentOp,proceedOp.param2);
replaceOp(op); affiche(textOnScreen);
}
concDigit=false; isDouble=false;
}
private void percentage(){
if(proceedOp==null){
textOnScreen="0";
affiche(textOnScreen);
}else if(proceedOp.param2==null){
if(proceedOp.percent==null){
proceedOp.percent=eval(proceedOp.param1,"*","0.01");
textOnScreen=proceedOp.param2=eval(proceedOp.param1,"*",proceedOp.percent);
}else{
textOnScreen=proceedOp.param2=eval(proceedOp.param1,"*",proceedOp.percent);
}
affiche(textOnScreen);
}else{if(proceedOp.lastOp=="="){
proceedOp.percent=eval(proceedOp.param1,"*","0.01");
textOnScreen=proceedOp.param2=eval(textOnScreen,"*",proceedOp.percent);
affiche(textOnScreen);
}else{
proceedOp.percent=eval(proceedOp.param2,"*","0.01");
textOnScreen=proceedOp.param2=eval(proceedOp.param1,"*",proceedOp.percent);
affiche(textOnScreen);
}
}
if(proceedOp!=null){
proceedOp.lastOp=null;}
concDigit=false;
}
private void comma(){
if(isDouble==false){
if(concDigit==false){textOnScreen="0";}
affiche(textOnScreen);
isDouble=true;currCharIsCom=true;concDigit=true;
}
}
private void manageMemory(String memInfo){
if((memInfo.charAt(memInfo.length()-1))=='C'){
memory="0";((JLabel)features[23]).setText(" ");
}else if((memInfo.charAt(memInfo.length()-1))=='R'){
textOnScreen=memory;
affiche(textOnScreen);
}else if((memInfo.charAt(memInfo.length()-1))=='S'){
memory=textOnScreen;if(Double.parseDouble(memory)!=0){((JLabel)features[23]).setText(" M");}
}else if(memory!=null){
memory=eval(memory,"+",textOnScreen);if(Double.parseDouble(memory)!=0){((JLabel)features[23]).setText(" M");}}
concDigit=false;if(Double.parseDouble(memory)==0){((JLabel)features[23]).setText(" ");}
}
private void manageErasers(String erInfo){
if((erInfo.equals("Backspace"))==true&&concDigit){
if(currCharIsCom){currCharIsCom=false;}else
if(textOnScreen.length()==1||(textOnScreen.length()==2&&textOnScreen.charAt(0)=='-')){textOnScreen="0";affiche(textOnScreen);concDigit=false;}else{
if(currCharIsCom){currCharIsCom=false;}else {if(textOnScreen.charAt(textOnScreen.length()-2)==','){isDouble=false;
}
textOnScreen=textOnScreen.substring(0,textOnScreen.length()-1);affiche(textOnScreen);}
}
if(!(proceedOp==null)){proceedOp.param2=textOnScreen;}
}else if((erInfo.equals("CE"))==true){
if(proceedOp!=null&&proceedOp.lastOp!="="){proceedOp.param2="0";}textOnScreen="0";affiche(textOnScreen);
isDouble=false; concDigit=false;
}else if(!(erInfo.equals("Backspace"))){
proceedOp=null;textOnScreen="0";affiche(textOnScreen);isDouble=false; concDigit=false;}
}
}
concDigit=false; isDouble=false;
}
private void percentage(){
if(proceedOp==null){
textOnScreen="0";
affiche(textOnScreen);
}else if(proceedOp.param2==null){
if(proceedOp.percent==null){
proceedOp.percent=eval(proceedOp.param1,"*","0.01");
textOnScreen=proceedOp.param2=eval(proceedOp.param1,"*",proceedOp.percent);
}else{
textOnScreen=proceedOp.param2=eval(proceedOp.param1,"*",proceedOp.percent);
}
affiche(textOnScreen);
}else{if(proceedOp.lastOp=="="){
proceedOp.percent=eval(proceedOp.param1,"*","0.01");
textOnScreen=proceedOp.param2=eval(textOnScreen,"*",proceedOp.percent);
affiche(textOnScreen);
}else{
proceedOp.percent=eval(proceedOp.param2,"*","0.01");
textOnScreen=proceedOp.param2=eval(proceedOp.param1,"*",proceedOp.percent);
affiche(textOnScreen);
}
}
if(proceedOp!=null){
proceedOp.lastOp=null;}
concDigit=false;
}
private void comma(){
if(isDouble==false){
if(concDigit==false){textOnScreen="0";}
affiche(textOnScreen);
isDouble=true;currCharIsCom=true;concDigit=true;
}
}
private void manageMemory(String memInfo){
if((memInfo.charAt(memInfo.length()-1))=='C'){
memory="0";((JLabel)features[23]).setText(" ");
}else if((memInfo.charAt(memInfo.length()-1))=='R'){
textOnScreen=memory;
affiche(textOnScreen);
}else if((memInfo.charAt(memInfo.length()-1))=='S'){
memory=textOnScreen;if(Double.parseDouble(memory)!=0){((JLabel)features[23]).setText(" M");}
}else if(memory!=null){
memory=eval(memory,"+",textOnScreen);if(Double.parseDouble(memory)!=0){((JLabel)features[23]).setText(" M");}}
concDigit=false;if(Double.parseDouble(memory)==0){((JLabel)features[23]).setText(" ");}
}
private void manageErasers(String erInfo){
if((erInfo.equals("Backspace"))==true&&concDigit){
if(currCharIsCom){currCharIsCom=false;}else
if(textOnScreen.length()==1||(textOnScreen.length()==2&&textOnScreen.charAt(0)=='-')){textOnScreen="0";affiche(textOnScreen);concDigit=false;}else{
if(currCharIsCom){currCharIsCom=false;}else {if(textOnScreen.charAt(textOnScreen.length()-2)==','){isDouble=false;
}
textOnScreen=textOnScreen.substring(0,textOnScreen.length()-1);affiche(textOnScreen);}
}
if(!(proceedOp==null)){proceedOp.param2=textOnScreen;}
}else if((erInfo.equals("CE"))==true){
if(proceedOp!=null&&proceedOp.lastOp!="="){proceedOp.param2="0";}textOnScreen="0";affiche(textOnScreen);
isDouble=false; concDigit=false;
}else if(!(erInfo.equals("Backspace"))){
proceedOp=null;textOnScreen="0";affiche(textOnScreen);isDouble=false; concDigit=false;}
}
private void affiche(String toPrint){
boolean printComma=true; if(toPrint==null){System.out.println("nullpointer");}
for(int i=0;i<toPrint.length();i++){if(toPrint.charAt(i)=='.'){printComma=false;}}
if(printComma){toPrint+=".";}
String space=display.getText();
for(int j=0;toPrint.length()<50;j++){toPrint=" "+toPrint;}
display.setText(updateComma(toPrint));
}
boolean printComma=true; if(toPrint==null){System.out.println("nullpointer");}
for(int i=0;i<toPrint.length();i++){if(toPrint.charAt(i)=='.'){printComma=false;}}
if(printComma){toPrint+=".";}
String space=display.getText();
for(int j=0;toPrint.length()<50;j++){toPrint=" "+toPrint;}
display.setText(updateComma(toPrint));
}
private void replaceOp(String op){
if(proceedOp==null){proceedOp=new Operation(textOnScreen,op,null);}else{
proceedOp=new Operation(textOnScreen,op,null);}
}
private String eval(String par1,String op,String par2){
String result="";double r=0, op1=(Double.parseDouble(par1)), op2=Double.parseDouble(par2);
if(op.equals("+")){r= op1 + op2;}
if(op.equals("*")){r= op1 * op2;System.out.println(r);}
if(op.equals("-")){r= op1 - op2;}
if(op.equals("/")){if(op2==0&&op1==0){result="Result of function is undefined";}else if(op2==0){result="Cannot divide by zero";}else{r= op1 / op2;}}
if(result.equals("")){ result+=r; }
char c=' ';
for(int i=0; i<result.length();i++){if(result.charAt(i)=='E'){c='E';}}
if(c!='E'){
for(int i=0; i<result.length();i++){if(result.charAt(i)=='.'&&Double.parseDouble(result.substring(i+1,result.length()))==0){result=result.substring(0,i+1);i=result.length();}}
}
return result;
}
private String eval(String par1,String op){
String result="";double r=0, op1=(Double.parseDouble(par1));
if(op.equals("+/-")){r= op1-2*op1 ;}
if(op.equals("1/x")){if(op1==0){result="Cannot divide by zero";}else{r= 1 / op1;}}
if(op.equals("sqrt")){if(op1<0){result="invalid input for function";}else{r=Math.sqrt(op1);}}
if(result.equals("")){ result+=r; }
char c=' ';
for(int i=0; i<result.length();i++){if(result.charAt(i)=='E'){c='E';}}
if(c!='E'){
for(int i=0; i<result.length();i++){if(result.charAt(i)=='.'&&Double.parseDouble(result.substring(i+1,result.length()))==0){result=result.substring(0,i);i=result.length();}}
}
return result;
}
private void manageDigits(String digit){
if(textOnScreen.length()<33){
if(concDigit){if(currCharIsCom){textOnScreen+=".";}
textOnScreen+=digit;if(Double.parseDouble(textOnScreen)==0&&!isDouble){textOnScreen="0";concDigit=false;}}else{
textOnScreen=digit;if(Double.parseDouble(textOnScreen)!=0){concDigit=true;}} if(proceedOp!=null){if(!("=").equals(proceedOp.lastOp)){proceedOp.param2=textOnScreen;}}
affiche(textOnScreen); currCharIsCom=false;
}else if(proceedOp!=null){if(proceedOp.param2==null){textOnScreen=digit;manageDigits(digit);}}
}
private void equal(){
if(proceedOp!=null){
if(proceedOp.param2==null){proceedOp.param2=textOnScreen;}
proceedOp.lastOp="=";
textOnScreen=proceedOp.param1=eval(proceedOp.param1,proceedOp.currentOp,proceedOp.param2);
}
affiche(textOnScreen);concDigit=false;currCharIsCom=false;isDouble=false;
}
private String updateComma(String toReturn){
for(int i=0;i<toReturn.length();i++){if(toReturn.charAt(i)==','){toReturn=toReturn.substring(0,i)+"."+toReturn.substring(i+1,toReturn.length());i=toReturn.length();}
if(i<toReturn.length()){ if(toReturn.charAt(i)=='.'&&i<toReturn.length()){toReturn=toReturn.substring(0,i)+","+toReturn.substring(i+1,toReturn.length());i=toReturn.length();}}}
return toReturn;
}
/**
* methode main
*/
public static void main(String[] argv)
{
new calculator();
}
}//Des tests s'imposent! ajouter une fonctionalitee scientifique
