CODEWITHSUNDEEP
javaarraysfor-loopprintf
James Duval
James Duval

Reputation: 87

Java silently failing to print from array

I'm trying to convert an integer into an array of digits, then print those digits out in order. It's an early problem in Java: How to Program, and I'm confused as to why I can't make it work.

Here's my class:

public class AnyDigits {
    private int[] ns;

    public AnyDigits(int n){
        this.ns = new int[String.valueOf(n).length()];
        for(int i = 0, x = n; x > 0; i++, x = x / 10){
            this.ns[i] = x % 10;
        }
    }
    public void printDigits(){
        for(int i = this.ns.length - 1; i == 0; i--){
            System.out.printf("%d ", this.ns[i]);
        }
    }
}

I have this code in my main method:

AnyDigits digitsTest = new AnyDigits(42339);
digitsTest.printDigits();

Any comments on the organisation, style and formatting of my code are also welcomed.

Any help gratefully received!

Upvotes: 0

Views: 81

Answers (2)

Saj
Saj

Reputation: 18712

Another way aside from BackSlash's answer-

private static int[] makeArrayFromInt(final int val){

    String temp = String.valueOf(val);

    int[] digits = new int[temp.length()];

    for(int i = 0; i < temp.length(); i++){
        digits[i] = Integer.parseInt(temp.substring(i, i + 1));
    }

    return digits;

}

Test:

int[] digits = makeArrayFromInt(12234);
for(int i = 0; i < digits.length; i++){
    System.out.println(digits[i]);
}

Upvotes: 2

BackSlash
BackSlash

Reputation: 22243

for(int i = this.ns.length - 1; i == 0; i--){
    System.out.printf("%d ", this.ns[i]);
}

This won't work, you are iterating while i==0, i will never be 0 at the first loop unless this.ns.length == 1.

You need 

for(int i = this.ns.length - 1; i != 0; i--){
    System.out.printf("%d ", this.ns[i]);
}

or

for(int i = this.ns.length - 1; i >= 0; i--){
    System.out.printf("%d ", this.ns[i]);
}

Anyway, if you want to print an array, you can just do

System.out.println(Arrays.toString(yourArray));

Upvotes: 4

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