where is the bug?

[Antony Amicone]

i've 2 class, in class ProgCalc i've got a method that set a choose from a menu. I create "t" an object TimeOfDay, and i get its value, than i create another object TimeOfDay "t1". t1 overwrite t... why?

 import java.io.*;
 
public class ProgTime {
 
private static int h;
private static int m;
private static int s;
private static boolean isSetted = false;
private static TimeOfDay t,t1;
private static int addseconds;
 
public static void printHome() {
 
//method that write a menu
//and call the method  setChoose
}
 
public static void setChoose() {
try {
InputStreamReader input = new InputStreamReader(System.in);
BufferedReader reader = new BufferedReader(input);
int choose = Integer.parseInt(reader.readLine());
while (!(choose > 0 && choose < 9)) {
System.out.println("Hai selezionato un valore errato: "
+ choose);
System.out.println("Reinserire un valore corretto :\r");
choose = Integer.parseInt(reader.readLine());
}
if (choose == 1) {
createDate();
t = new TimeOfDay(h, m, s);
isSetted = true;
printHome();
}
if (isSetted == true) {
if (choose == 2) {
System.out
.println("Il valore richiesto e': " + t.getTime());
interval();
printHome();
}

[B]if (choose == 7) {
//here i have already created t
//than i print it, create t1 and reprint t and t1. 
//but t1 has now overwritten t
// why???
createDate();
System.out.println("il tempo e'"+t.getTime());
t1 = new TimeOfDay(h,m,s);
System.out.println("il tempo 1 e'"+t.getTime());
System.out.println("il tempo e'"+t1.getTime());
System.out.println("Il valore richiesto e': "
+ t.secondsFrom(t1));
interval();
printHome();
}[/B]
} else {
System.out.println("Devi prima settare un orario");
interval();
printHome();
}
 
} catch (Exception ioexc) {
System.out
.println("Il programma ha generato un errore. Inserire il valore numerico corrispondente al menu scelto\r");
printHome();
}
 
}
 
public static void createDate() {
try {
boolean validTime = false;
InputStreamReader input = new InputStreamReader(System.in);
BufferedReader reader = new BufferedReader(input);
while (!validTime) {
System.out.println("Inserisci le ore");
h = Integer.parseInt(reader.readLine());
System.out.println("Inserisci i minuti");
m = Integer.parseInt(reader.readLine());
System.out.println("Inserisci i secondi");
s = Integer.parseInt(reader.readLine());
if ((h >= 0 && h < 23) && (m >= 0 && m < 59)
&& (s >= 0 && s < 59)) {
validTime = true;
} else {
System.out
.println("Inserire valori numerici corretti.");
}
}
 
} catch (Exception e) {
System.out.println("Inserire un valore numerico corretto");
}
}

public static void main(String[] args) {
printHome();
 
}
 
}   

-----------------------------------

  import java.util.Date;
 
public class TimeOfDay {
 
private static int hours;
private static int minutes;
private static int seconds;
private static String time;
private static boolean isValid = true;
private static int secondsChange;
private static String tempT;
private static TimeOfDay time2;
private static int secondsFrom;

public TimeOfDay(int h,int m,int s){
hours = h;
minutes = m;
seconds = s;
if (!(hours>=0 && hours<24)){
System.out.println("\rIl valore delle ore non e' corretto");
isValid = false;
hours = 0;
}
if (!(minutes>=0 && minutes<59)){
System.out.println("\rIl valore dei minuti non e' corretto");
isValid = false;
minutes = 0;
}
if (!(seconds>=0 && seconds<59)){
System.out.println("\rIl valore dei secondi non e' corretto");
isValid = false;
seconds = 0;
}
}
public TimeOfDay(){
hours = 0;
minutes = 0;
seconds = 0;
}
public static String getTime(){
time = getHours() + ":"+ getMinutes() + ":" + getSeconds();
return time;
}
public static int getHours(){
return hours;
}
public static int getMinutes(){
return minutes;
}
public static int getSeconds(){
return seconds;
}
public static int secondsFrom(TimeOfDay t){
time2 = t;
int totalSecond = ( ( ( hours * 60 ) +  minutes ) * 60 ) + seconds;
int totalSecond1 = ( ( ( t.getHours() * 60 ) +  t.getMinutes() ) * 60 ) + t.getSeconds();
if ( totalSecond <= totalSecond1 ){
secondsFrom = totalSecond1 - totalSecond; 
}
else { secondsFrom = totalSecond - totalSecond1; }
return secondsFrom;
}
}
  

[ March 27, 2006: Message edited by: Antony Amicone ]

[Ernest Friedman-Hill]

If a member variable is "static", it means it is shared by all instances of the class. Therefore although t and t1 are pointing to distinct instances of your class, they share all their member data. If t makes a change, t1 sees that change, and vice-versa.

Remove every single instance of "static" in the TimeOfDay class, and things will be fixed -- or at least close to fixed. Then go back and remove every single use of "static" in ProgTime, as well, except for the one in "public static void main()". Finally, change the call to printHome() to something like

new ProgTime().printHome();

and you'll be in great shape!

[Henry Wong]

All your "TimeOfDay" variables are static, there is one set for all your instances. Hence, changing one, changes all of them.

Henry

[Antony Amicone]

it runs!!! tnx a lot to everyone...
I made it without static, but eclipse gave me errors on method calling in main, because i only wrote printHome();

tnx a lot...

by the way, when it is better to set static a method?

[Antony Amicone]

so... the inverse problem with this one

  import java.io.*;
 
public class ProgCalc {

private double val1;
private double val2;
private double res;

// Il metodo printHome disegna la home del programma, dove l'utente pu�
// visionare il menu di scelta.
public void printHome() {
//this method print a menu and call setChoose()
}

public void setOp() {
try {
InputStreamReader input = new InputStreamReader(System.in);
BufferedReader reader = new BufferedReader(input);
System.out.println("\rInserisci il primo valore: ");
val1 = Integer.parseInt(reader.readLine());
System.out.println("\rInserisci il secondo valore: ");
val2 = Integer.parseInt(reader.readLine());
System.out.println("I due valori sono stati inseriti correttamente.");
} 
catch (Exception ioexc) {
System.out.println("Inserire un valore numerico corretto");
printHome();
}
}

public void setChoose() {
try {
InputStreamReader input = new InputStreamReader(System.in);
BufferedReader reader = new BufferedReader(input);
int choose = Integer.parseInt(reader.readLine());
while (!(choose > 0 && choose < 8)) {
System.out.println("Hai selezionato un valore errato: "
+ choose);
System.out.println("Reinserire un valore corretto :\r");
choose = Integer.parseInt(reader.readLine());
}
if (choose == 7) { 
System.out.println("Ciao!");
System.exit(0);
}
if (choose == 2) { 
setOp();

[B]//THIS BOLD PART IS VIEWED AS ERROR
//it says "cannot make a static reference to a non static method
//how to correct?[/B]
 
res = [B]Calcolatrice.sum(val1,val2);[/B]
System.out.println("Il risultato e': "+res);
interval();
printHome();
}
if (choose == 3) { 
setOp();
res = [B]Calcolatrice.sub(val1,val2);[/B]
System.out.println("Il risultato e': "+res);
interval();
printHome();
}

} catch (Exception ioexc) {
System.out.println("Il programma ha generato un errore. Inserire il valore numerico corrispondente al menu scelto\r");
printHome();
}
 
}

public static void main(String[] args) {
new ProgCalc().printHome();
}
 
}
  

  public class Calcolatrice {
 
private double op1;
private double op2;
private double res;
private boolean isValid = true;
 
// descrivo i metodi della classe
public double sum(double a, double b) {
op1 = a;
op2 = b;
res = op1 + op2;
return res;
}
 
public double sub(double a, double b) {
op1 = a;
op2 = b;
res = op1 - op2;
return res;
}
 
public boolean isValid() {
return isValid;
}
}
  

[ March 27, 2006: Message edited by: Antony Amicone ]

[Antony Amicone]

ok i'm and idiot... i've not written the creation of the object calcolatrice...
now i've made it all resolved tnx all