Thread: some help please

hi every one i'm new member and i'm beginner in java

i have a problem in me code and i don't know how to deal with it


this is the question


In this project, write a Java program that will convert an input metric to a corresponding value in the International System of Units. Input metric will be in Yards, Inches, Miles, and Pounds. The converted metric should be converted as follows:
Table 1:

Input Metric


Output Metric


Yards


Meters


Inches


Centimeters


Miles


Kilometers


Pounds


Kilogram



The program should display a Menu for the user to choose from the above metric. The menu is shown in the figure below.



Welcome to Multi conversion System
Press c for Inches to Centimeters
Press m for Yards to Meters
Press k for Miles to Kilometers
Press g for Pounds to Kilograms

The user has to enter c, m, k, or g. Next, the user will enter a value for the input metric which the program will convert to the specified unit from table 1. The output of the program should be the converted metric value. In addition, consider the following scenarios in the output:
1. If the user inputs a character that is not recognized (NOT c, m, k, or g), then the program prints “Wrong Selection!”, and exits.
2. If the user inputs a value less than zero for a metric, the program will display a message that states “Cannot convert a negative value!”
3. After displaying the converted metric value (if input value is not negative), the program should also display the range of the converted value according to the following rules:
a. If converted value is less than 20, print “Less than 20.”
b. If converted value is less than 50, print “Less than 50.”
c. If converted value is equal 50, print “Equal 50”.
d. If converted value is greater than 50, print “Greater than 50.”
Hint 1: To read a character using a Scanner input, use the following statement:
char c = input.nextLine().charAt(0);
Hint 2: To convert a metric use the following formulas:
Centimeters = 2.54 * inches
Meters = 0.9144 * Yards
Kilometers = 1.60934 * Miles
Kilograms = 0.453592 * Pounds

Note: Submit only the source code. For example: IA_1110348_P2.java
Sample Program Run #1:



Welcome to Multi conversion System
Press c for Inches to Centimeters
Press m for Yards to Meters
Press k for Miles to Kilometers
Press g for Pounds to Kilograms

k
Enter a value in Miles: 10
Your 10.0 Miles are 16.0934 Kilometers. Less than 20.

Sample Program Run #2:
Welcome to Multi conversion System
Press c for Inches to Centimeters
Press m for Yards to Meters
Press k for Miles to Kilometers
Press g for Pounds to Kilograms

y
Wrong Selection!






Sample Program Run #3:
Welcome to Multi conversion System
Press c for Inches to Centimeters
Press m for Yards to Meters
Press k for Miles to Kilometers
Press g for Pounds to Kilograms

g
Enter a value in Miles: -20
Cannot convert a negative value!

Sample Program Run #4:
Welcome to Multi conversion System
Press c for Inches to Centimeters
Press m for Yards to Meters
Press k for Miles to Kilometers
Press g for Pounds to Kilograms




c
Enter a value in Inches: 100
Your 100.0 Inches are 254.0 Centimeters. Greater than 50.



and i have try many times to solve it and every time i failed

 import java.util.Scanner;
import javax.swing.JOptionPane;
 
/**
 *
 * @author Mac
 */
public class EA_1211835_P2 {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
 
        double yardes,inches,miles,pounds,meters,centimeters,kilogram,kilometers;
 
        char c,m,k,g;
 
        String x;
 
        Scanner in = new Scanner(System.in);
 
        x=JOptionPane.showInputDialog(null, 
                "please press c for centimeters , g for kilogram , k for kilometers , m for meters ");
 
    c=in.nextLine().charAt(0);
 
     m=in.nextLine().charAt(0);
 
     k=in.nextLine().charAt(0);
 
     g=in.nextLine().charAt(0);
 
     if (c<20)
 
     {
       c=inches*2.45;
     }
 
 
 
 
    }
}

please help me

I see your code.
I see the assignment instructions.
I see your complaint.
I see you want help.
I do not see what you are stuck on, what you need help with, or what your question is.

I don't know how to complete the assignment

Can you be a bit more specific than that? What exactly don't you understand? A golden rule of thumb is to try to put as much effort into asking your question as you'd like a volunteer to expend answering it.

this is my code

import java.util.Scanner;
import javax.swing.JOptionPane;
 
/**
 *
 * @author Mac
 */
public class EA_1211835_P2 {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
 
        double yardes,inches,miles,pounds,meters,centimeters,kilogram,kilometers;
 
        char c,m,k,g;
 
        String x;
 
        Scanner in = new Scanner(System.in);
 
        x=JOptionPane.showInputDialog(null, "please press c for centimeters , g for kilogram , k for kilometers , m for meters");
 
 
 
 
        c=in.nextLine().charAt(0);
 
     m=in.nextLine().charAt(0);
 
     k=in.nextLine().charAt(0);
 
     g=in.nextLine().charAt(0);
 
     if (c=='c') {
            centimeters=2.45*inches;
        }
 
 
 
 
     {}

the problem is i can't get the result's and when i use if and else if the program say else with out if

Originally Posted by zezo

when i use if and else if the program say else with out if

can you describe your if problem a little more, please?

Could you not use a switch statement for the letter choices and have the default case print "invalid selection"

Originally Posted by zezo

this is my code

import java.util.Scanner;
import javax.swing.JOptionPane;
 
/**
 *
 * @author Mac
 */
public class EA_1211835_P2 {
 
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
 
        double yardes,inches,miles,pounds,meters,centimeters,kilogram,kilometers;
 
        char c,m,k,g;
 
        String x;
 
        Scanner in = new Scanner(System.in);
 
        x=JOptionPane.showInputDialog(null, "please press c for centimeters , g for kilogram , k for kilometers , m for meters");
 
 
 
 
        c=in.nextLine().charAt(0);
 
     m=in.nextLine().charAt(0);
 
     k=in.nextLine().charAt(0);
 
     g=in.nextLine().charAt(0);
 
     if (c=='c') {
            centimeters=2.45*inches;
        }
 
 
 
 
     {}

the problem is i can't get the result's and when i use if and else if the program say else with out if

There is no else in the posted code. You will have to post the code you have questions about if you want help with it.