Adding 2 Number In Java

HI PPL

I DID A SIMPLE PROGRAM THAT ADD 2 NUMBER BUT I AM HAVING PROBLEM IN ENTER THE NUMBER FROM THE USER

Code: ( text )

import java.io.*;
public class cal{
int a=0;
int b=0;
int c=0;
a =reader.readLine();
b =reader.readLine();
c =a+b;
system.out.println(c);
}

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
the error in the reader.readline();

in c++ you just have to write cin>>a>>

i am new in java and i really dont know what to do

sukatoa

Needs Regular Fix

456 Posts

April 5th, 2008
03:42 PM
#2

Re: Adding 2 Number In Java

Quote:

Originally Posted by LOVE4EVER

HI PPL

I DID A SIMPLE PROGRAM THAT ADD 2 NUMBER BUT I AM HAVING PROBLEM IN ENTER THE NUMBER FROM THE USER

Code: ( text )

import java.io.*;
public class cal{
int a=0;
int b=0;
int c=0;
a =reader.readLine();
b =reader.readLine();
c =a+b;
system.out.println(c);
}

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
the error in the reader.readline();

in c++ you just have to write cin>>a>>

i am new in java and i really dont know what to do

Welcome to java forum.... :)

You can start to read Scanner class.

Look for Scanner( inputstream s) Constructor.....

Read also about "System.in", " Integer.parseInt( String s ) ".....
try to browse again about object and class in java on how they will be used...

Try to have some experiment on this

Code: ( text )

Scanner scan = new Scanner(System.in);
String num1 = scan.nextLine();
int integervalue = Integer.parseInt( num1 );

Don't forget to import the built-in Scanner class....

Update us...
sukatoa

LOVE4EVER

Newbie

5 Posts

April 5th, 2008
04:43 PM
#3

Re: Adding 2 Number In Java

thx for the information a lot sukatoa its really helped me

now the code is like this

Code: ( text )

import java.io.*;
import java.util.Scanner;
public class cal{
Scanner read = new Scanner(system.in);
int a =read.nextInt();
int b =read.nextInt();
int c =a+b;
system.out.println(c);
}

there are 2 errors
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
cal.java:12: <identifier> expected
system.out.println(c);
^
cal.java:12: <identifier> expected
system.out.println(c);
^
2 errors
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
how (c) can be identifier!!!

sukatoa

Needs Regular Fix

456 Posts

April 6th, 2008
03:48 AM
#4

Re: Adding 2 Number In Java

Quote:

Originally Posted by LOVE4EVER

thx for the information a lot sukatoa its really helped me

now the code is like this

Code: ( text )

import java.io.*;
import java.util.Scanner;
public class cal{
Scanner read = new Scanner(system.in);
int a =read.nextInt();
int b =read.nextInt();
int c =a+b;
system.out.println(c);
}

You forgot to change the "s". It should be System.

Just a reminder bro: Java is case sensitive.... :)

regards,
sukatoa....

Laharl

Expert

733 Posts

April 6th, 2008
04:11 AM
#5

Re: Adding 2 Number In Java

Also, you don't need to import java.io.*, since the Scanner is handling input and System.out.println handles output (the System class is included by default). Imports are like C(++)'s #includes, if you're not using anything from them, don't import/#include them. It's not a huge deal now, but it's just good practice not to import more than you need, as it slows down your code (especially if you import java.*...or javax.*...).

LOVE4EVER

Newbie

5 Posts

April 6th, 2008
10:52 AM
#6

Re: Adding 2 Number In Java

i did all the things you told me guys but i am still having the same errors

this is the the new code

Code: ( text )

import java.util.Scanner;
public class cal{
Scanner read = new Scanner(System.in);
int a =read.nextInt();
int b =read.nextInt();
int c =a+b;
System.out.println (c);
}

2 errors
>>>>>>>>>>>>>>>>>>>>>>>>
Exception in thread "main" java.lang.NoClassDefFoundError: cal
Caused by: java.lang.ClassNotFoundException: cal
at java.net.URLClassLoader$1.run(URLClassLoader.java: 200)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.j ava:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:3 06)
at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:276)
at java.lang.ClassLoader.loadClass(ClassLoader.java:2 51)
at java.lang.ClassLoader.loadClassInternal(ClassLoade r.java:319)

C:\DOCUME~1\mes\java>javac cal.java
cal.java:9: <identifier> expected
System.out.println (c);
^
cal.java:9: <identifier> expected
System.out.println (c);
^
2 errors

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

JosAH

Chief Editor

7,525 Posts

April 6th, 2008
11:18 AM
#7

Re: Adding 2 Number In Java

Take a Java tutorial before you start banging your keyboard: Java classes have
methods and methods have statements. You can't put statements just at the
class level, i.e. it doesn't make sense to the compiler.

kind regards,

Jos

sukatoa

Needs Regular Fix

456 Posts

April 6th, 2008
11:30 AM
#8

Re: Adding 2 Number In Java

Quote:

Originally Posted by LOVE4EVER

i did all the things you told me guys but i am still having the same errors

this is the the new code

Code: ( text )

import java.util.Scanner;
public class cal{
Scanner read = new Scanner(System.in);
int a =read.nextInt();
int b =read.nextInt();
int c =a+b;
System.out.println (c);
}

Those error may be avoided if you put those codes inside a method....
You forgot also to have main method....

Jos' recommendation may lead you to the right way....

After reading, applying what you've learn,

Update us about your new code.....
sukatoa...

LOVE4EVER

Newbie

5 Posts

April 6th, 2008
12:14 PM
#9

Re: Adding 2 Number In Java

i talled you guys i am new in java i used to programming in c++ and when i did
this very simple program i was using my information about c++ but never mind i didnt copy this problem without reading java tutorial but maybe you are see it simple problem for you but for me its not and i did a program that compute the result without the user enter the number but any way thx for help and the information its really helpful and of cource in the final i will have a code without errors

JosAH

Chief Editor

7,525 Posts

April 6th, 2008
12:25 PM
#10

Re: Adding 2 Number In Java

Quote:

Originally Posted by LOVE4EVER

i talled you guys i am new in java i used to programming in c++ and when i did
this very simple program i was using my information about c++ [ ... ]

C++ (and C and BCPL and CPL and C#) also have statements in functions/methods only.
Java is no exception. Please don't imagine how a language could/should work,
read the authorative standards on it and only then try to implement something.
Even more: before you implement anything at all you should design it first, just
using scrapbook paper and a pencil. The actual typing in of your program should
be a boring task and should be finished asap.

Most people don't do that: they have a vague idea and they start banging their
keyboards with the only result that they're tied to that damned thing during long
complicated debug sessions until 'something' more or less working is the result.
Don't follow that path because all you'll create are ugly little monstrosities.

kind regards,

Jos

LOVE4EVER

Newbie

5 Posts

April 7th, 2008
09:29 AM
#11

Re: Adding 2 Number In Java

i understant now why the errors because there is no method so i put the method and its really nice to see that no errors in the code but when i open the .class file it give me this statment
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Exception in thread "main" java.lang.NoSuchMethodError: main

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

and this is the code

Code: ( text )

import java.util.Scanner;
public class cal{
public static void main(int [] args)
{
Scanner read = new Scanner(System.in);
int a =read.nextInt();
int b =read.nextInt();
int c =a+b;
System.out.println(c);
}
}

why its not working ?

JosAH

Chief Editor

7,525 Posts

April 7th, 2008
09:35 AM
#12

Re: Adding 2 Number In Java

Quote:

Originally Posted by LOVE4EVER

Code: ( text )

import java.util.Scanner;
public class cal{
public static void main(int [] args)
{
Scanner read = new Scanner(System.in);
int a =read.nextInt();
int b =read.nextInt();
int c =a+b;
System.out.println(c);
}
}

why its not working ?

The single argument to the main() method has type String[] not int[]. The JVM
checks that.

kind regards,

Jos

Kid Programmer

Familiar Sight

174 Posts

May 14th, 2008
08:06 PM
#15

Re: Adding 2 Number In Java

Quote:

Originally Posted by LOVE4EVER

HI PPL

I DID A SIMPLE PROGRAM THAT ADD 2 NUMBER BUT I AM HAVING PROBLEM IN ENTER THE NUMBER FROM THE USER

Code: ( text )

import java.io.*;
public class cal{
int a=0;
int b=0;
int c=0;
a =reader.readLine();
b =reader.readLine();
c =a+b;
system.out.println(c);
}

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
the error in the reader.readline();

in c++ you just have to write cin>>a>>

i am new in java and i really dont know what to do

You are becoming a help vampire. But to get this over with just copy and paste this code:

Code: ( text )

import java.util.Scanner;
public class cal {
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
double a, b, c;
a = scan.nextDouble();
b = scan.nextDouble();
c = a + b;
System.out.println(c);
}
}

It should work perfectly :-) Good luck programming.

Geethu03

Member

40 Posts

May 15th, 2008
06:44 AM
#17

Re: Adding 2 Number In Java

Use this i think it will help you. Pls follow this code

Code: ( text )

import java.io.*;
public class cal{
public static void main(String arg[]) throws IOException {
int a=0;
int b=0;
int c=0;
DataInputStream ds = new DataInputStream(System.in());
a =Integer.parseInt(ds.readLine());
b =Integer.parseInt(ds.readLine());
c =a+b;
system.out.println(c);
}

Quote:

Originally Posted by LOVE4EVER

HI PPL

I DID A SIMPLE PROGRAM THAT ADD 2 NUMBER BUT I AM HAVING PROBLEM IN ENTER THE NUMBER FROM THE USER

Code: ( text )

import java.io.*;
public class cal{
int a=0;
int b=0;
int c=0;
a =reader.readLine();
b =reader.readLine();
c =a+b;
system.out.println(c);
}

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
the error in the reader.readline();

in c++ you just have to write cin>>a>>

i am new in java and i really dont know what to do

JosAH

Chief Editor

7,525 Posts

May 15th, 2008
07:09 AM
#18

Re: Adding 2 Number In Java

Quote:

Originally Posted by Geethu03

Use this i think it will help you. Pls follow this code

I bet you didn't read reply #16 by Lahari and no, you don't need DataInputStreams
when you want to read text from user's input.

kind regards,

Jos

Kid Programmer

Familiar Sight

174 Posts

May 16th, 2008
02:55 AM
#19

Re: Adding 2 Number In Java

Quote:

Originally Posted by Laharl

Kid, after five weeks, either he's gotten the answer himself or he's given up and gone elsewhere. Regardless, we don't just give boilerplate code here and tell the OP to copy/paste.

Well he never said he found the answer and it had gone of for long enough. I figured I might as well just end it. If he has questions about my code I can answer them.