Stupid question in java
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moussecp
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javabaka -
javabaka -
Hello,
It's silly, but I can create classes, manage a lot of things and all... but I don't know which line of code allows the user of the program to input values.
An example to be a bit clearer.
Let's say I want at a certain point in my program for the user to input two numbers that will be added together and displayed on the screen...
Well, I don't know how to do that. In C++, you have to do something like
but in Java, no idea...
Does anyone know how to help me?
Thanks.
It's silly, but I can create classes, manage a lot of things and all... but I don't know which line of code allows the user of the program to input values.
An example to be a bit clearer.
Let's say I want at a certain point in my program for the user to input two numbers that will be added together and displayed on the screen...
Well, I don't know how to do that. In C++, you have to do something like
int a, b; cin >> a >> b >> endl; cout << a+b << endl;
but in Java, no idea...
Does anyone know how to help me?
Thanks.
Configuration: Windows XP Firefox 2.0.0.12
2 réponses
Hello,
It's true that if you don't know, it's not easy.
You need to use the Scanner class (there are other solutions using streams (InputStream...), but this one is not too complicated).
In your Java program, you need to import the Scanner class (available starting from Java 5)
That is: import java.util.*;
Then in your program do:
Scanner scan=new Scanner(System.in);
//Then use scan to read what you want, for example:
String s=scan.next(); //Expects a string
int nb=scan.nextInt(); //Expects a number
...
...
...
You have other methods to read other things; to know about them, check the Java 5 or 6 API
or if you are developing in Eclipse, you can see them
P.S.: For it to work, you must be developing in JAVA 5 or higher.
It's true that if you don't know, it's not easy.
You need to use the Scanner class (there are other solutions using streams (InputStream...), but this one is not too complicated).
In your Java program, you need to import the Scanner class (available starting from Java 5)
That is: import java.util.*;
Then in your program do:
Scanner scan=new Scanner(System.in);
//Then use scan to read what you want, for example:
String s=scan.next(); //Expects a string
int nb=scan.nextInt(); //Expects a number
...
...
...
You have other methods to read other things; to know about them, check the Java 5 or 6 API
or if you are developing in Eclipse, you can see them
P.S.: For it to work, you must be developing in JAVA 5 or higher.
I use a BufferedReader
example:
if you want an int from the keyboard, you do:
and to make sure it's a number, you enclose it in a try-catch block (handle exceptions)
example:
String file = ""; BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What is the name of your file?"); file = keyboard.readLine(); if you want an int from the keyboard, you do:
int file = ""; BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in)); System.out.println("What is the number of your file?"); file = Integer.parseInt(keyboard.readLine()); and to make sure it's a number, you enclose it in a try-catch block (handle exceptions)
At first glance, I thought it looked really complicated for something so simple, but in the end, it's really easy.
Thank you again.