Swap the word in the String

Question

input:-
1
Ans kot

Output:-
kot Ans

INPUT : the first line of the input contains the number of test cases. Each test case consists of a single line containing the string.

OUTPUT : output the string with the words swapped as stated above.**

Code:-

Scanner sc = new Scanner(System.in);
int a = sc.nextInt();
StringBuffer result = new StringBuffer();
for (int i = 0; i < a; i++) {
    String b = sc.next();
    String my[] = b.split(" ");
    StringBuffer r = new StringBuffer();
    for (int j = my.length - 1; j > 0; j--) {
        r.append(my[j] + " ");
    }
    r.append(my[0] + "\n");
    result.append(r.toString());
}
System.out.println(result.toString());
}

What is wrong in my code ? above is code which i am trying.

You can design a function which reverse *a single word*; lets call it ```reverser(String):String``` then call it for every word. — Manu, Jul 13 '15 at 07:24
You're not trying to reverse a word, but a sequence of words. — Tim, Jul 13 '15 at 07:26

score 2 · Answer 1 · answered Jul 13 '15 at 07:28

2

String my[] = b.split(" ");
StringBuffer r = new StringBuffer();
for (int j = my.length - 1; j > 0; j--) {
    r.append(my[j] + " ");
}

this snippet of your code is only gonna reverse the sentence "word by word" not "character by character". therefore, you need reverse the string (my[j]) before you append it into the StringBuffer

answered Jul 13 '15 at 07:28

kucing_terbang

4,487
2
19
27

@kucing-terbang any specific reason you have used `StringBuffer` instead of `StringBuilder` ? – Ram Patra Jul 13 '15 at 07:37
@Ramswaroop No reason, I just copy pasted from the OP's code. – kucing_terbang Jul 13 '15 at 07:38

score 1 · Answer 2 · answered Jul 13 '15 at 07:29

1

Use this

 Scanner sc = new Scanner(System.in);
            int a = sc.nextInt();
            sc.nextLine();
            StringBuffer result = new StringBuffer();
            for (int i = 0; i < a; i++) {
                String b = sc.nextLine();
                String my[] = b.split(" ");
                StringBuffer r = new StringBuffer();
                for (int j = my.length - 1; j > 0; j--) {
                    r.append(my[j] + " ");

                }
                r.append(my[0] + "\n");
                result.append(r.toString());
            }
            System.out.println(result.toString());
        }

answered Jul 13 '15 at 07:29

Nightswatch

111
1
5

But why with next it is not working... and nextLine it is working... can u explain it – ansh Jul 13 '15 at 07:33
Using next() will only return what comes before a space. nextLine() automatically moves the scanner down after returning the current line. – Nightswatch Jul 13 '15 at 07:35
http://stackoverflow.com/questions/22458575/whats-the-difference-between-next-and-nextline-methods-from-scanner-class – Nightswatch Jul 13 '15 at 07:35

score 0 · Answer 3 · answered Jul 13 '15 at 07:27

Takes String input and return String in reverse order of each characters.

String reverse(String x) {
        int i = x.length() - 1;
        StringBuilder y = new StringBuilder();
        while (i >= 0) {
            y.append(x.charAt(i));
            i--;
        }

        return y.toString();
    }

score 0 · Answer 4 · answered Jul 13 '15 at 07:33

public static String reverseWords(String input) {
    Deque<String> words = new ArrayDeque<>();
    for (String word: input.split(" ")) {
        if (!word.isEmpty()) {
            words.addFirst(word);
        }
    }
    StringBuilder result = new StringBuilder();
    while (!words.isEmpty()) {
        result.append(words.removeFirst());
        if (!words.isEmpty()) {
            result.append(" ");
        }
    }
    return result.toString();
}

score 0 · Answer 5 · answered Jul 13 '15 at 07:34

0

You can run this code:

String[] splitted = yourString.split(" ");

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

answered Jul 13 '15 at 07:34

The Dr.

635
1
10
24

score 0 · Accepted Answer · answered Jul 13 '15 at 07:34

Multiple things:

You are using next api which will just read your string that you type word by word and you loop until a i.e. in your example just once. So instead use nextLine api which will read whole line instead of just a word and then split by space:
```
String b = sc.nextLine();
```
You are reading input with nextInt api followed by enter, you you might sometime end up having return character when reading next token using next api. Instead use:
```
int a = Integer.parseInt(sc.nextLine());
```
You are using StringBuffer which has an overhead of obtaining mutex and hence should use StringBuilder.

score 0 · Answer 7 · answered Jul 13 '15 at 08:02

Code:-
               
    Scanner sc =new Scanner(System.in);
        int a =Integer.parseInt(sc.nextLine());
        StringBuffer result= new StringBuffer();
        for (int i = 0; i <a; i++) {
     String b=sc.nextLine();
        String my[]= b.split(" ");
        StringBuffer r = new StringBuffer();
     for (int j = my.length-1; j >0; j--) {
      r.append(my[j]+" ");
      
     }
     r.append(my[0] + "\n");
          result.append(r.toString());
    }
     System.out.println(result.toString());
   

enter code here

Swap the word in the String

7 Answers7