Page 1 of 1
Need Java Help - Prompting User for Input
Posted: Tue Sep 11, 2007 4:20 am
by Cooldown
I've taken a Comp Sci course this semester which covers Java. While we haven't started to learn the actual code and syntax, I decided to jump ahead. I have a little experience with C++ and Java from Comp Sci from HS, but it's been a while so everything is a little bit hazy so bear with me.
What I want to do is simple--prompt the user to enter an integer (or String then convert it to an integer). Then store the input in a variable. This is what I have....if there is
better way to do this then by all means...I'm open ears
Code: Select all
import java.io.*;
import java.util.*;
public class problem1
{
public static void main (String[] args)
{
InputStreamReader stdin = new InputStreamReader(System.in);
BufferedReader console = new BufferedReader(stdin);
System.out.println("Enter a number");
String input = stdin.readLine();
int number = Integer.parseInt(input);
System.out.println(number);
}
}
I get the following error:
Code: Select all
C:\Java>javac problem1.java
problem1.java:12: cannot find symbol
symbol : method readLine()
location: class java.io.InputStreamReader
String input = stdin.readLine();
^
1 error
I've searched on Google and attempted to look up for answer on why this is happening to no avail. Everything seems right, why am I getting an error?
Re: Need Java Help - Prompting User for Input
Posted: Tue Sep 11, 2007 10:29 am
by ^misantropia^
Make that line console.readLine() and it should compile fine. console is an instance of BufferedReader, stdin of InputStreamReader.
Re: Need Java Help - Prompting User for Input
Posted: Tue Sep 11, 2007 10:31 am
by ^misantropia^
Also, this bit:
Code: Select all
InputStreamReader stdin = new InputStreamReader(System.in);
BufferedReader console = new BufferedReader(stdin);
is superfluous.
Code: Select all
BufferedReader console = new BufferedReader(System.in);
is sufficient.
Re: Need Java Help - Prompting User for Input
Posted: Tue Sep 11, 2007 7:04 pm
by Cooldown
Thanks! Seems that I also need throws IOException after (String args[]).
And apparently I need both
Code: Select all
InputStreamReader stdin = new InputStreamReader(System.in);
BufferedReader console = new BufferedReader(stdin);
Otherwise, I get an error.
Code: Select all
import java.io.*;
import java.util.*;
public class prob2
{
public static void main (String[] args) throws IOException
{
InputStreamReader stdin = new InputStreamReader(System.in);
BufferedReader console = new BufferedReader(stdin);
System.out.print("Enter a number: ");
String input = console.readLine();
int number = Integer.parseInt(input);
System.out.print(number);
}
}
This compiles fine.
Re: Need Java Help - Prompting User for Input
Posted: Tue Sep 11, 2007 7:34 pm
by Cooldown
I'm having difficulty with an if statement.
Code: Select all
import java.io.*;
import java.util.*;
public class prob2
{
public static void main (String[] args) throws IOException
{
InputStreamReader stdin = new InputStreamReader(System.in);
BufferedReader console = new BufferedReader(stdin);
System.out.print("Enter a number:");
String input = console.readLine();
int number = Integer.parseInt(input);
System.out.println(number);
System.out.println("Do you like cheese? (Y/N):");
String coupon = console.readLine();
if (coupon == "N" || coupon == "n"){
System.out.print("You don't like cheese.");
}
else{
System.out.print("You like cheese.");
}
}
The output is not as desired. If I enter "N" or 'n' as my input to the "Do you like cheese? (Y/N):" question it ends up outputting "I like cheese."
Re: Need Java Help - Prompting User for Input
Posted: Tue Sep 11, 2007 7:51 pm
by ^misantropia^
Thanks! Seems that I also need throws IOException after (String args[]).
You don't. And don't want to. Google for
checked exceptions. Rule of thumb: catch any non-fatal exceptions, only let the real show stoppers pass through:
Code: Select all
try {
console.readLine();
} catch (IOException e) {
e.printStackTrace();
}
A tip: compiling with -Xlint:all lets the compiler catch most bad coding practices. And use the
Java coding conventions, your future co-workers will like you better for it (plus, it'll help you get a job easier).
Re: Need Java Help - Prompting User for Input
Posted: Thu Sep 13, 2007 3:42 am
by Cooldown
Okay, got my problems solved.
^misantropia^ , what IDE do you prefer to use when programming in Java, if any?
Re: Need Java Help - Prompting User for Input
Posted: Thu Sep 13, 2007 11:26 am
by ^misantropia^
joe 
And NetBeans. The integration with Tomcat rocks.