plz help me in my project

[smart princess]

Hello
i wrote this program to find the age and when my teacher saw it he said it's true but you have to add 1 (if) for each month that's mean 12 (if) and put in your maind the year that has 28 days in Feb. I don't understand why we need 12(if) and how can i do this program plz help me i need it during this week to submit it ,,,

//this programe will find your age
import java.util.*;
public class Age1{
public static void main(String[] args){
int x,y,z,s,m,k,a,d,r;
String name;
Scanner scan=new Scanner(System.in);
System.out.println("Enter your name");
name=scan.nextLine();
do{
System.out.println("Enter the day of the month your born on");
x=scan.nextInt();
if(x<=0||x>31){
System.out.println("oobs there are no date like this");
}
}while(x<=0||x>31);
do{
System.out.println("Enter the month you born in");
y=scan.nextInt();
if(y<=0||y>31){
System.out.println("oobs there are no date like this");
}
}while(y<=0||y>31);
do{
System.out.println("Enter the year you born in");
z=scan.nextInt();
if(z<=0||z>2011){
System.out.println("oobs there are no date like this");
}
}while(z<=0||z>2011);
do{
System.out.println("Enter the date of today");
s=scan.nextInt();
if(s<=0||s>31){
System.out.println("oobs there are no date like this");
}
}while(s<=0||s>31);
do{
System.out.println("Enter this month");
m=scan.nextInt();
if(m<=0||m>31){
System.out.println("oobs there are no date like this");
}
}while(m<=0||m>31);
do{
System.out.println("Enter this year");
k=scan.nextInt();
if(k<=0||k>2011){
System.out.println("You are not born right now :)");
}
}while(k<=0||k>2011);
r=s-x;
if(r<0){
r=x-s;
}
a=m-y;
if(a<0){
a=y-m;
}
d=k-z;
System.out.println("Dear "+name+" your age is "+d+" year\n and "+a+" month \n and "+r+" day");
}
}

[sky]

Repost your code uisng the [CODE] tag please.

[smart princess]

Repost your code uisng the [CODE] tag please.

ok

//this programe will find your age
import java.util.*;
public class Age1{
  public static void main(String[] args){
    int x,y,z,s,m,k,a,d,r;
   String name;
    Scanner scan=new Scanner(System.in);
    System.out.println("Enter your name");
    name=scan.nextLine();
      do{
    System.out.println("Enter the day of the month your born on");
    x=scan.nextInt();
    if(x<=0||x>31){
      System.out.println("oobs there are no date like this");
    }
      }while(x<=0||x>31);
      do{
    System.out.println("Enter the month you born in");
    y=scan.nextInt();
    if(y<=0||y>31){
      System.out.println("oobs there are no date like this");
    }
      }while(y<=0||y>31);
      do{
    System.out.println("Enter the year you born in");
    z=scan.nextInt();
    if(z<=0||z>2011){
      System.out.println("oobs there are no date like this");
    }
      }while(z<=0||z>2011);
      do{
    System.out.println("Enter the date of today");
    s=scan.nextInt();
    if(s<=0||s>31){
      System.out.println("oobs there are no date like this");
    }
      }while(s<=0||s>31);
      do{
    System.out.println("Enter this month");
    m=scan.nextInt();
    if(m<=0||m>31){
      System.out.println("oobs there are no date like this");
    }
      }while(m<=0||m>31);
      do{
    System.out.println("Enter this year");
    k=scan.nextInt();
    if(k<=0||k>2011){
      System.out.println("You are not born right now :)");
    }
    }while(k<=0||k>2011);
     r=s-x;
    if(r<0){
      r=x-s;
    }
    a=m-y;
    if(a<0){
      a=y-m;
    }
    d=k-z;
    System.out.println("Dear "+name+" your age is "+d+" year\n and "+a+" month \n and "+r+" day");
  }
}

[sky]

First of all. You should give your variables names like "days" "months", etc. that way the code is much more readable. Second: When you do the substraction of the months and years, you can just take the absolute value instead of use an if. And finally, I think that what the teacher wanted to say is that when you read the days from the user:

if(x<=0||x>31){
      System.out.println("oobs there are no date like this");
    }

That is a bad error control, because there are months with 30 days, months with 31 days and then February that can has 29 on the leap years. To know if a year is a leap year, I found the following algorithm in the Wikipedia:

if year modulo 400 is 0 then leap
 else if year modulo 100 is 0 then no_leap
 else if year modulo 4 is 0 then leap
 else no_leap