Number of digits code

Question

I have a problem asking me to tell the amount of digits in a given number. I inserted conditional statements, but no matter what number I insert, it gives me "nine" digits. The code is below. I'm a math student and not computer science, so I figure I'm not using the most efficient method.

import java.util.Scanner;

public class E52 {
    public static void main(String[] args) {
        // part 1: import scanner
        Scanner sc = new Scanner(System.in);

        // part 2: ask user for a number
        System.out.println("Please enter a number: ");
        int number = sc.nextInt();

        // part 3: tell how many digits are in each number by using string and conditional statements
        String number1Str;
        if (number >= 0 || number <= 10) number1Str = "one";
        if (number >= 10 || number <= 100) number1Str = "two";
        if (number >= 100 || number <= 1000) number1Str= "three";
        if (number >= 1000 || number <= 10000) number1Str = "four";
        if (number >= 10000 || number <= 100000) number1Str = "five";
        if (number >= 100000 || number <= 1000000) number1Str = "six";
        if (number >= 1000000 || number <= 10000000) number1Str = "seven";
        if (number >= 10000000 || number <= 100000000) number1Str = "eight";
        if (number >= 100000000 || number <= 1000000000) number1Str = "nine";
        else number1Str = "undefined";

        System.out.println("There are " + number1Str + " digits in the given number.");

        sc.close();
    }
}

Logic error. Your `||` should be `&&`. Because you want a logical and, not a logical or. — Elliott Frisch, Sep 08 '17 at 17:02
It would also be a lot simpler if you used `else if` - then you'd only need a single condition in each test. — Jon Skeet, Sep 08 '17 at 17:04
this seems seriously complicated in order to do what you need, but I'm not a java dev. Can you not cast it as a string and determine the length? — Robert Wade, Sep 08 '17 at 17:04
@RobertWade converting it to `String` and using the `length()` method would sure do the trick but I'd assume this is some kind of exercise or homework given. — Ousmane D., Sep 08 '17 at 17:06
@ElliottFrisch I did that but now it is giving me "undefined" digits. — Elijah Dover, Sep 08 '17 at 17:06
@ElijahDover Use && instead of ||. Also use else if instead of separate if. — user3437460, Sep 08 '17 at 17:07
@JonSkeet How would you do else if? My professor doesn't explain these things but hands out homework on it anyways. — Elijah Dover, Sep 08 '17 at 17:08
`if (number < 0) { return "negative"; } else if (number < 10) { return "one";} else if (number < 100) { return "two"; } etc` — Jon Skeet, Sep 08 '17 at 17:10

score 1 · Answer 1 · answered Sep 08 '17 at 17:09

It would be much easier to create an Array, then get the input's length and pick let it pick the entry:

Scanner sc = new Scanner(System.in);

// part 2: ask user for a number
System.out.println("Please enter a number: ");
Integer number = sc.nextInt();
final String[] numNames = {
            "",
            "one",
            "two",
            "three",
            "four",
            "five",
            "six",
            "seven",
            "eight",
            "nine",
            "ten",
            "eleven",
            "twelve",
            "thirteen",
            "fourteen",
            "fifteen",
            "sixteen",
            "seventeen",
            "eighteen",
            "nineteen"
    };
System.out.println(numNames[number.toString().length()]);

Well, there are zillions of ways to do that. Very much depends on what his homework expects him to do. In case he has to use if/else ... your solution is pointless. — GhostCat, Sep 08 '17 at 17:10

score 0 · Answer 2 · edited Sep 08 '17 at 17:14

0

This will give you number count no matter how big or small number is. Although there are corner scenarios which may fail the code but i still feel this will be of use to you in some other way around

public class CountNum {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String numAsString = sc.nextLine();
        System.out.println(numAsString.length());
        sc.close();
    }

}

edited Sep 08 '17 at 17:14

kaza

2,317
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answered Sep 08 '17 at 17:08

Aditya Ajmera

44
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And when his assignment asks for using if/else .. your answer doesnt help him. – GhostCat Sep 08 '17 at 17:10
Agree.. If the whole point is for teaching if-else and operators, it would not make sense to proceed in this way. :) – Aditya Ajmera Sep 08 '17 at 17:13
@GhostCat where does he say the assignment required if/else? He even admitted he's probably using an inefficient method which implies it was of his own choosing. He simply stated he needed to find the number of digits. – Robert Wade Sep 08 '17 at 17:13
Note: I didn't downvote. I am just talking out of experience. When newbies focus on a certain pattern - then often because they are asked to do so. – GhostCat Sep 08 '17 at 17:21

Number of digits code

2 Answers2