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Thread: How to set value of double to 2 decimal places

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    Default How to set value of double to 2 decimal places

    How can I make the value of double 2 decimal places? I know how to display 2 decimal places, but how to actually set the values to 2?

    Example, my change below is 7.93

    So it knows the dollar is 7, but for the cent, it's showing 0.9299999999999997 instead of .93

    double change = 7.93;
     
    int dollar;
    double cent;
    dollar = (int)change % 1000000;
    cent = change - dollar;
     
    System.out.println("Dollar " + dollar);
    System.out.println("Cent " + cent);

    Dollar 7
    Cent 0.9299999999999997


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    Default Re: How to set value of double to 2 decimal places

    Representing money.

    If you must use double, look at printf() for formatting output and explore the topic "rounding" for conditioning the values to be what you want.

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    Default Re: How to set value of double to 2 decimal places

    Quote Originally Posted by GregBrannon View Post
    Representing money.

    If you must use double, look at printf() for formatting output and explore the topic "rounding" for conditioning the values to be what you want.
    Thank you

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    Default Re: How to set value of double to 2 decimal places

    Shouldn't cent be: 92.99999999999997
    That is a dollar amount: 0.9299999999999997
    If you don't understand my answer, don't ignore it, ask a question.

  5. The Following User Says Thank You to Norm For This Useful Post:

    tonynsx (November 19th, 2013)

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    Default Re: How to set value of double to 2 decimal places

    Quote Originally Posted by Norm View Post
    Shouldn't cent be: 92.99999999999997
    That is a dollar amount: 0.9299999999999997
    If I have, 77.92, the 77 is the dollar, then .92 is the cent. Unless my calculations are wrong above.

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    Default

    You misunderstood what Norm was saying.

    Cents should be an integer. Do I give you 92 cents or .92 of a cent?

  8. The Following 2 Users Say Thank You to Kewish For This Useful Post:

    Norm (November 19th, 2013), tonynsx (November 19th, 2013)

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    Default Re: How to set value of double to 2 decimal places

    Quote Originally Posted by Kewish View Post
    You misunderstood what Norm was saying.

    Cents should be an integer. Do I give you 92 cents or .92 of a cent?
    Thanks for clearing that up, yes I did misunderstood.

    --- Update ---

    Now it's working the way I want. Please let me know if I can improve on anything.

    Change: 88.38, Dollar: 88, getCent: 37
    1 $50
    1 $20
    1 $10
    1 $5
    3 $1
    1 $0.25
    1 $0.10
    2 $0.01

    package correctchange;
     
    public class CorrectChange {
     
        public static void main(String[] args) {          
     
            double change = 88.38;
     
            int dollar,cent;
            double getCent;
            dollar = (int)change % 1000000;
            getCent = (change - dollar) * 100;
            cent = (int)(getCent);
     
            System.out.println("Change: " + change + ", Dollar: " + dollar + ", getCent: " + cent);
     
            // dollar calculation
     
            if((dollar / 100) >= 1)
            {
                System.out.println(dollar / 100 + " $100");
                dollar = dollar - 100 * (dollar / 100);
            }
     
            if((dollar / 50) >= 1)
            {
                System.out.println(dollar / 50 + " $50");
                dollar = dollar - 50 * (dollar / 50);
            }
     
            if((dollar / 20) >= 1)
            {
                System.out.println(dollar / 20 + " $20");
                dollar = dollar - 20 * (dollar / 20);
            }
     
            if((dollar / 10) >= 1)
            {
                System.out.println(dollar / 10 + " $10");
                dollar = dollar - 10 * (dollar / 10);
            }
     
            if((dollar / 5) >= 1)
            {
                System.out.println(dollar / 5 + " $5");
                dollar = dollar - 5 * (dollar / 5);
            }
     
            if((dollar / 1) >= 1)
            {
                System.out.println(dollar / 1 + " $1");
            }
     
            // getCents calculation     
     
            if((cent / 25) >= 1)
            {
                System.out.println((cent / 25) + " $0.25");
                cent = cent - 25 * (cent / 25);
            }
     
            if((cent / 10) >= 1)
            {
                System.out.println((cent / 10) + " $0.10");
                cent = cent - 10 * (cent / 10);
            }
     
            if((cent / 5) >= 1)
            {
                System.out.println((cent / 5) + " $0.05");
                cent = cent - 5 * (cent / 5);
            }
     
            if((cent / 1) >= 1)
            {
                System.out.println((cent / 1) + " $0.01");
            }
     
        }
     
    }


    --- Update ---

    Just found another problem. I gave test value of 19.83. But. Instead of 83 it's showing 82 for cents

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    Default Re: How to set value of double to 2 decimal places

    Quote Originally Posted by tonynsx View Post

    getCent = (change - dollar) * 100;
    cent = (int)(getCent);

    Just found another problem. I gave test value of 19.83. But. Instead of 83 it's showing 82 for cents
    That is because your double is being truncated and not rounded. You need to think about how you will handle your rounding before casting to an integer.

    What is the value of (change - dollar) * 100; before you typecast? Use a print statement. It will become obvious what is going on. Handle your rounding then typecast.

    Hint: Math Class

    Also, what is the theory behind the % 1 Million? What if the change is 1,000,001.83? How many dollars will you have?

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    tonynsx (November 20th, 2013)

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    Default Re: How to set value of double to 2 decimal places

    Thanks, Math.round() worked!

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    Default

    Welcome

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