Reversing ouput of string token

Question

The following prints out the entered sentence in order. I need it to print the input in reverse order:

import java.util.Scanner;


public class Sentence {
    public static void main(String [] args) {
        Scanner input = new Scanner(System.in);
        System.out.print("Enter a sentence: ");
        String sentence = input.nextLine();

        String[] tokens = sentence.split(" ");
        System.out.println(tokens.length);

        for (String token : tokens) {
            System.out.println(token);
        }   
    }
}

It's not clear what you want. Please provide input and desired output. — Robert Kock, Oct 18 '18 at 14:50
The code I have now ask them to enter a sentence. Lets say they enter "My name is Andrew", it prints out as My name is Andrew — Andrew DeWitt, Oct 18 '18 at 14:52
Possible duplicate of [How do I reverse an int array in Java?](https://stackoverflow.com/questions/2137755/how-do-i-reverse-an-int-array-in-java) — Markus, Oct 18 '18 at 14:55

score 2 · Accepted Answer · answered Oct 18 '18 at 14:54

2

Use a regular for loop and print from last index to first index:

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

answered Oct 18 '18 at 14:54

Eritrean

15,851
3
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Thank you for the help. Much appreciated. That gives me the output I was looking for. – Andrew DeWitt Oct 18 '18 at 15:11

Puremonk · Answer 2 · 2018-10-18T14:59:04.737

2

You're printing the tokens in the order of the sentence, in no way do you reverse it. Try looping it in reverse

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

edited Oct 18 '18 at 14:59

answered Oct 18 '18 at 14:55

Puremonk

163
1
1
8

@Eritrean beat me to it. – Puremonk Oct 18 '18 at 14:55
1

`tokens.length` without brackets – Robert Kock Oct 18 '18 at 14:56
You're right. Fixed. – Puremonk Oct 18 '18 at 14:59
Thank you both for the help – Andrew DeWitt Oct 18 '18 at 15:11

score 0 · Answer 3 · answered Oct 18 '18 at 14:57

You can use this to reverse your sentence. It will print: sentence a is This

    String sentence = "This is a sentence";

    String[] tokens = sentence.split(" ");
    System.out.println(tokens.length);

    for (int i = tokens.length-1; i >= 0; --i) {
        System.out.print(tokens[i]);
        System.out.print(" ");
    }

Reversing ouput of string token

3 Answers3