add two integers

[sridhar19]

i need add two integers in java codeing

[r035198x]

i need add two integers in java codeing

Are you having any specific problems with it? Does the user have to supply the integers or are hardcoding the integers to be added in there.

[JosAH]

i need add two integers in java codeing

For primitive 'int's your question is hilarious; for Integers have a look at autoboxing,
i.e. starting at Java 1.5 you can simply do this:

[code=java]
Integer a= new Integer(41);
Integer b= new Integer(13);
Integer c;

c= a+b;
[/code]

For Java < 1.5 you have to do this:

[code=java]
Integer a= new Integer(41);
Integer b= new Integer(13);
Integer c;

c= new Integer(a.intVa lue()+b.intValu e());
[/code]

kind regards,

Jos

[blazedaces]

For primitive 'int's your question is hilarious; for Integers have a look at autoboxing,
i.e. starting at Java 1.5 you can simply do this:

[code=java]
Integer a= new Integer(41);
Integer b= new Integer(13);
Integer c;

c= a+b;
[/code]

For Java < 1.5 you have to do this:

[code=java]
Integer a= new Integer(41);
Integer b= new Integer(13);
Integer c;

c= new Integer(a.intVa lue()+b.intValu e());
[/code]

kind regards,

Jos

I didn't know this, just tested it out, but you can even do the following:

[code=java]
public class testIntegerAddi ng {

public static void main(String args[]) {
Integer a = new Integer(13);
Double b = new Double(12.5);

Double c = a + b;
System.out.prin tln(c);
}
}
[/code]

-blazed

[JosAH]

I didn't know this, just tested it out, but you can even do the following:

[code=java]
public class testIntegerAddi ng {

public static void main(String args[]) {
Integer a = new Integer(13);
Double b = new Double(12.5);

Double c = a + b;
System.out.prin tln(c);
}
}
[/code]

-blazed

Autoboxing is a disease; have a look at this:

[code=java]
Integer a = 42, b = 42;
Integer c = 129, d = 129;
System.out.prin tln( a == 42 ); // true
System.out.prin tln( a == b ); // true
System.out.prin tln( c == 129 ); // true
System.out.prin tln( c == d ); // false
[/code]

kind regards,

Jos

[r035198x]

Autoboxing is a disease; have a look at this:

[code=java]
Integer a = 42, b = 42;
Integer c = 129, d = 129;
System.out.prin tln( a == 42); // true
System.out.prin tln( a == b ); // true
System.out.prin tln( c == 129 ); // true
System.out.prin tln( c == d ); // false
[/code]

kind regards,

Jos

Hey, I can't test this now but does a == 10 really give true?

[JosAH]

Hey, I can't test this now but does a == 10 really give true?

Ten? I don't see no ten in my post! :-P seriously though, that was a typo; I
remembered that silly example and typed it in from the top of my head.
10 should be 42. The results still are surprising.

kind regards,

Jos

[r035198x]

Ten? I don't see no ten in my post! :-P seriously though, that was a typo; I
remembered that silly example and typed it in from the top of my head.
10 should be 42. The results still are surprising.

kind regards,

Jos

Yep, when both operands are reference types no autoboxing occurs.

[JosAH]

Yep, when both operands are reference types no autoboxing occurs.

That's not the reason: auto(un)boxing only occurs when one of the types isn't
a reference type, e.g. Integer vs int. Here's a better example:

[code=java]
public boolean check(Integer x, Integer y) {

if (!(x < y || y < x))
return x == y; // most certainly x == y
else
return false // most certainly x != y
}
...
Integer x= 42, y= 42;
System.out.prin tln(check(x, y)); // true;

Integer x= 142, y= 142;
System.out.prin tln(check(x, y)); // false;
[/code]

kind regards,

Jos ;-)

[r035198x]

That's not the reason: auto(un)boxing only occurs when one of the types isn't
a reference type, e.g. Integer vs int. Here's a better example:

[code=java]
public boolean check(Integer x, Integer y) {

if (!(x < y || y < x))
return x == y; // most certainly x == y
else
return false // most certainly x != y
}
...
Integer x= 42, y= 42;
System.out.prin tln(check(x, y)); // true;

Integer x= 142, y= 142;
System.out.prin tln(check(x, y)); // false;
[/code]

kind regards,

Jos ;-)

I still don't see how my reason is different from the one you gave.

[JosAH]

I still don't see how my reason is different from the one you gave.

It's not about autoboxing itself: the puzzle is about why is 42 == 42 true while
142 == 142 is false. for both cases (x < y || y < x) is false (so mathematically
speaking x == y should be true.

kind regards,

Jos

[r035198x]

Oh yeah, I've tested it now with

[CODE=java]class Test {
public static void main(String[] args) {
Integer x= 127, y= 127;
System.out.prin tln(check(x, y));
Integer a= 128, b= 128;
System.out.prin tln(check(a, b));
}
public static boolean check(Integer x, Integer y) {
if (!(x < y || y < x))
return x == y;
else
return false ;
}
}[/CODE]
I should have known you were up to your tricks again.

[JosAH]

Oh yeah, I've tested it now with

[CODE=java]class Test {
public static void main(String[] args) {
Integer x= 127, y= 127;
System.out.prin tln(check(x, y));
Integer a= 128, b= 128;
System.out.prin tln(check(a, b));
}
public static boolean check(Integer x, Integer y) {
if (!(x < y || y < x))
return x == y;
else
return false ;
}
}[/CODE]
I should have known you were up to your tricks again.

Cute eh? That's why I wrote that autoboxing is a disease. ;-)

kind regards,

Jos

[r035198x]

Cute eh? That's why I wrote that autoboxing is a disease. ;-)

kind regards,

Jos

It has always looked suspicious.
I'm always suspicious of everything that begins with auto. Except for automobile of course.

[blazedaces]

It's not about autoboxing itself: the puzzle is about why is 42 == 42 true while
142 == 142 is false. for both cases (x < y || y < x) is false (so mathematically
speaking x == y should be true.

kind regards,

Jos

I didn't try it... but why does 142 == 142 output false? Btw, is autoboxing the process which checks "=="? I'm confused...

-blazed