Thread: Need help with loops and turning into roman numerals

Hello all,

I am relatively new and need some help with this. It is not allowing me to have two separate inputs. Enter "Name" and "Date". It for some reason is showing up on the same line.

Thanks for the help

package javaapplication7;
import java.util.Scanner;
 
/**
 *
 * @author Onlyname
 */
public class JavaApplication7 {
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        Scanner scan = new Scanner(System.in);
 
        // Input for name
        System.out.print("Name: "); 
        String Name="";
 
        // Input for Date
        System.out.print("Date: ");
        String Date="";
 
        int number = scan.nextInt();
 
        // Roman variable assignment
        String roman="";
 
        if (number<=1900 || number>2100) {
            System.out.println("Invalid. You must enter numbers between 1900 & 2100");
            System.out.println("Enter another number now: ");
 
        }
        while (number>=1000){
            roman +="M";
            number-=1000;
        }
 
        while(number>=900){
            roman += "CM";
            number-=900;
        }
 
        while (number>=500){
            roman += "D";
            number-=500;
        }
 
        while (number>=100){
            roman += "C";
            number-=100;
        }
 
        while (number>=50){
            roman += "L";
            number-=50;
        }
 
        while (number>=10){
            roman += "X";
            number-=10;
        }
 
        while (number>=5){
        roman += "V";
        number-=5;
        }
 
        while (number>=1){
            roman += "I";
            number-=1;
        }
 
        return Name + roman;
    }
}

// Input for name
        System.out.print("Name: "); 
        String Name="";
 
        // Input for Date
        System.out.print("Date: ");
        String Date="";
 
        int number = scan.nextInt();

You never got the input from Name nor Date. The only input you got is for number.

You are trying to get the input of 3 different values at the same time, you can't do that, first you get Name then you get Date and then you get number. What is the Date variable for? you never use it.

They appear in the same line because you are using .print() which doesn't create new lines, if you are using .print() then you need to type \n for a jump of line. if you don't want to do that then use .println()

Take a look at this. You can see there are many different ways of printing to the screen. System.out.print does not contain a line break so anything displayed will show on the same line.

@onlyname,
You said you wanted to receive three inputs but you have programmed for only one input i.e. the number as taken care of by nextInt(). If you want the other two inputs you need to invoke the appropriate nextXxx() methods of the Scanner class.
You have logical error in your program.
Suppose I entered 2200. You print a message that says number is invalid. Then you enter the loop and try to print the roman letters.
Try to modify your program according to your requirements with the two hints listed earlier.

Syed.

The date is supposed to take any date from 1900 to 2100 and convert into roman numeral, whatever the date maybe; but it has to be within that range.

Originally Posted by syedbhai

Try to modify your program according to your requirements with the two hints listed earlier.

You need to do that for now haha.

But okay, lets do this.
You need to compile your program mentally from the section i quoted in my first post:

     // Input for name
        System.out.print("Name: "); 
        String Name="";
 
        // Input for Date
        System.out.print("Date: ");
        String Date="";
 
        int number = scan.nextInt();

you just printed out "Name: "
You declared a variable Name and assigned nothing to it.
you printed out "Date: " and there was no new line jump so, so far you have "Name: Date: " in screen.
you declared a variable Date and assigned nothing to it.
you declared a variable number and (for the first time) asked the user to input data which will be assigned to number.

so is like syad said, it is a logical problem, fix that and it will work. (by the way, you explained what Date is but you never used it in the entire code, you are using the variable number)

Thanks for the help!!

I got it to break lines and have 2 separate inputs. However, It is not returning the values that I am asking for in the end. It says "cannot not return value whose result type is void"? Is this a logical error as well.

Thanks again for the your time.

package javaapplication7;
import java.util.Scanner;
 
/**
 *
 * @author Onlyname
 */
public class JavaApplication7 {
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        Scanner scan = new Scanner(System.in);
 
        // Input for name
        System.out.print("Name: "); 
 
        String Name= scan.nextLine();
 
        // Input for Date
        System.out.print("Date: ");
 
 
 
        String Date= scan.nextLine();
 
 
        int number = scan.nextInt();
 
 
        // Roman variable assignment
        String roman="";
 
        if (number<=1900 || number>2100) {
            System.out.println("Invalid. You must enter numbers between 1900 & 2100");
            System.out.println("Enter another number now: ");
 
        }
        while (number>=1000){
            roman +="M";
            number-=1000;
        }
 
        while(number>=900){
            roman += "CM";
            number-=900;
        }
 
        while (number>=500){
            roman += "D";
            number-=500;
        }
 
        while (number>=100){
            roman += "C";
            number-=100;
        }
 
        while (number>=50){
            roman += "L";
            number-=50;
        }
 
        while (number>=10){
            roman += "X";
            number-=10;
        }
 
        while (number>=5){
        roman += "V";
        number-=5;
        }
 
        while (number>=1){
            roman += "I";
            number-=1;
        }
 
        return Name + roman;
    }
}

The main() method is by definition, void, and cannot return anything. But you're in luck, there's no reason to return anything. Instead of returning the result, assign it to a variable:

String result = Name + roman;

And then print the result, or skip assigning it to a variable, and simply print it:

System.out.println( "The result is: " + Name + roman );

hmmm,

So, I did this and I am still getting no result.

I actually had, the System.out.printIn(xxx) earlier, but something was wrong with my logic so I changed it to return. Which I had no idea that it couldnt return anything when i replaced system.out with "return" in the first place.

Does String result = Name + roman; need to be somewhere specific other than with the others?

It helps to post your updated code so that we know what changes you made. In place of your return, I used

System.out.println( Name + roman );

And I get a result. I can't imagine why you would not be.

[code = java]
package javaapplication7;
import java.util.Scanner;

/**
*
* @author Onlyname
*/
public class JavaApplication7 {
/**
* @param args the command line arguments
*/
public static void main(String[] args) {
// TODO code application logic here
Scanner scan = new Scanner(System.in);

// Input for name
System.out.print("Name: ");

String Name= scan.nextLine();

// Input for Date
System.out.print("Date: ");

int number = scan.nextInt();

// Roman variable assignment
String roman="";


if (number<=1900 || number>2100) {
System.out.println("Invalid. You must enter numbers between 1900 & 2100");
System.out.println("Enter another number now: ");


}
while (number>=1000){
roman +="M";
number-=1000;
}

while(number>=900){
roman += "CM";
number-=900;
}

while (number>=500){
roman += "D";
number-=500;
}

while (number>=100){
roman += "C";
number-=100;
}

while (number>=50){
roman += "L";
number-=50;
}

while (number>=10){
roman += "X";
number-=10;
}

while (number>=5){
roman += "V";
number-=5;
}

while (number>=1){
roman += "I";
number-=1;
}

System.out.println( "The result is: " + Name + roman );
}
}
[/code]

You made progress. I got 1959 = MCMLVIIII. That's not right. Close, but not right.

Yea, I made a minor mistake in that. I had a string after the date. So instead of there being an output it just kept looking for that variable. Now I have to figure this out. Thanks a lot for everyones help. I will probably be back later if I can't figure out future steps. Thanks greg