2 Simple Java questions

Question

First question: I am trying to print out four double values in reverse order so if the user enters "1 2 3 4" I want it to print out "4 3 2 1" Here is my coding.

// User enters 4 float values here
System.out.println("Enter 4 float values");
inputValues2 = input.readLine();
String[] dblValues = inputValues2.split("\\s+");

Second Question: I want to print out the integer portion of a double value. I guess I am trying to convert the double value to an int. I have tried these two different ways and get errors for both of them. Any ideas?? Maybe I should just do some sort of rounding to a whole number??

int dblConvert = dblAverage.intValue();           // One way
int dblConvert = Integer.parseInt(dblAverage);    // Second way

For the first part, what have you done so far? For the second one, simply cast your double to int: `(int) dblAverage`. You can call `dblAverage.intValue()` only on a `Double`, not on a `double` (note the capital D). — jhamon, Jan 21 '15 at 09:09
Please restrain to a _single_ question per question and give it a proper title. — Jens Erat, Jan 21 '15 at 09:12
@JensErat I would if I could ask more than 1 question every 90 minutes.... — Marcus Burkhart, Jan 21 '15 at 09:25
Better use the `nextInt()` method from `Scanner` to iterate over the items (storing the items for reverse order still needed). It will give you single integers even if seperated by multiple whitespaces. — KnutKnutsen, Jan 21 '15 at 09:26

Abimaran Kugathasan · Accepted Answer · 2015-01-21T09:15:32.040

9

Find the answers/hints for your questions.

You have to print the content of the array in reverse order.
```
for (int i = dblValues.length -1;i >= 0; i--) {
    System.out.println(dblValues[i]);
}
```
This is the fundamental way for a begginer. They are some predifined libraries to do this job
You can use int a = (int) Math.round(doubleVar);

edited Jan 21 '15 at 09:15

answered Jan 21 '15 at 09:06

Abimaran Kugathasan

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Thanks this is what I was looking for. I will accept answer in 9 min when I am allowed. – Marcus Burkhart Jan 21 '15 at 09:10
What if I am trying to not print out the variable here and just set the reverse of dblValues[i] for later use...? – Marcus Burkhart Jan 21 '15 at 09:21
@MarcusBurkhart, Yes, the initial value stored in that array location will be replaced by the newer value. You may try. – Abimaran Kugathasan Jan 21 '15 at 09:23
1

thanks again. Appreciate the help and quick responses. – Marcus Burkhart Jan 21 '15 at 09:24

score 0 · Answer 2 · edited May 23 '17 at 11:45

0

For your second question: there is a Math.round() method. You'll then need to cast the returned long to int in a safe way.

edited May 23 '17 at 11:45

Community

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answered Jan 21 '15 at 09:09

Villager

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score 0 · Answer 3 · answered Jan 21 '15 at 09:13

If you dont just want to print the numbers in reverse order and order them naturally you can add them to a list and sort them

If you also don't care about rounding you can just cast a double

    String s = "4 3 2 1";
    String[] split = s.split("\\s+");
    List<Integer> numbers = new LinkedList<>();

    for (String toAdd : split) {
        numbers.add(Integer.parseInt(toAdd));
    }       

    Collections.sort(numbers);      
    System.out.println(numbers);

    System.out.println((int)45.7654);

score 0 · Answer 4 · answered Jan 21 '15 at 09:13

1.) loop from last index and print in reverse order.

2.) Use Math.round() for getting int part

public static void main(String[] arg) {
        Scanner input = new Scanner(System.in);
        System.out.println("Enter 4 float values");
        String inputValues2 = input.nextLine();
        String[] dblValues = inputValues2.split("\\s+");

        System.out.println("Reverse order");

        for (int i = dblValues.length - 1 ; i >= 0 ; i--) {
            System.out.println(dblValues[i]);
        }

        System.out.println("int part ");

        for (String s : dblValues) {
            int a = Math.round(new Float(s));
            System.out.println(a);
        }
    }

output

Enter 4 float values
12.4 23.5 34.5 45.3
Reverse order
45.3
34.5
23.5
12.4
int part 
12
24
35
45

2 Simple Java questions

4 Answers4