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How to input a value for an integer variable

Posted on 2006-11-12
7
177 Views
Last Modified: 2010-03-31
Hi,
I want to have the user input length and width so that my program calculates area and perimeter of a rectangle. How do I write the input statements? Here is my code:

class Rectangle {
private int length;
private int width;

public Rectangle(int l, int w) {
length = l;
width = w;
}

public int calculateArea() {
return length * width;
}

public int calculatePerimeter() {
return (2 * length + 2 * width);
}

public static void main(String args[]) {
    int l,w,area,perimeter;
    System.out.println("Input length:");
    l = input.nextInt(); //????
    System.out.println("Input width:");
    w = input.nextInt();//????
    Rectangle rect = new Rectangle(l,w);
    area = rect.calculateArea();
    perimeter = rect.calculatePerimeter();
    System.out.println("The area of the rectangle is: ");
 
System.out.println(area);
System.out.println("The perimeter of the rectangle is: ");
System.out.println(perimeter);

}
}

Thank you.

0
Comment
Question by:aej1973
  • 3
  • 3
7 Comments
 
LVL 13

Expert Comment

by:kawas
ID: 17927365

quoting: http://javaalmanac.com/egs/java.io/ReadFromStdIn.html

e34. Reading Text from Standard Input

    try {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        String str = "";
        while (str != null) {
            System.out.print("> prompt ");
            str = in.readLine();
            process(str);
        }
    } catch (IOException e) {
    }
0
 
LVL 13

Expert Comment

by:kawas
ID: 17927372
the method process(str) would be the place that you would do something like:

try {
len = Integer.parseInt(str) ;
} catch (Exception e) {
// bad input
}
0
 

Author Comment

by:aej1973
ID: 17927425
Do I have to include or import any files to use the above code?
0
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LVL 13

Expert Comment

by:kawas
ID: 17927430
java.io.BufferedReader
java.io.InputStreamReader
0
 

Author Comment

by:aej1973
ID: 17927449
This is my code. Where am I going wrong?

import java.io.BufferedReader;
import java.io.InputStreamReader;

class Rectangle {
private int length;
private int width;
public Rectangle(int l, int w) {
length = l;
width = w;
}
public int calculateArea() {
return length * width;
}
public int calculatePerimeter() {
return (2 * length + 2 * width);
}
public static void main(String args[]) {
    int l,w,area,perimeter;
    System.out.println("Input length:");
    try {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        String str = "";
        while (str != null) {
            System.out.print("> prompt ");
            str = in.readLine();
            process(str);
        }
    } catch (IOException e) {
    }

    System.out.println("Input width:");
    Rectangle rect = new Rectangle(l,w);
        area = rect.calculateArea();
        perimeter = rect.calculatePerimeter();
        System.out.println("The area of the rectangle is: ");
       
System.out.println(area);
System.out.println("The perimeter of the rectangle is: ");
System.out.println(perimeter);

}
}

0
 
LVL 13

Accepted Solution

by:
marchent earned 75 total points
ID: 17928243
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.IOException;

class Rectangle {
private int length;
private int width;
public Rectangle(int l, int w) {
length = l;
width = w;
}
public int calculateArea() {
return length * width;
}
public int calculatePerimeter() {
return (2 * length + 2 * width);
}
public static void main(String args[]) {
    int l,w,area,perimeter;
    try {
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
        System.out.print("Input Length : ");
        l = Integer.parseInt(in.readLine());
        System.out.print("Input width : ");
        w = Integer.parseInt(in.readLine());
        Rectangle rect = new Rectangle(l,w);
        area = rect.calculateArea();
        perimeter = rect.calculatePerimeter();
        System.out.println("The area of the Rectangle is : "+area);
        System.out.println("The perimeter of the Rectangle is : "+perimeter);
       
    } catch (Exception e) {
        System.out.println(e);
    }
}
}
0
 

Author Comment

by:aej1973
ID: 17929412
Thank you.
0

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