CODEWITHSUNDEEP
javastringcharstringbuilder
Jin
Jin

Reputation: 47

Adding a space after a specific character in a string

Basically, (dog)(cat)(mouse) needs to be (dog) (cat) (mouse).

My attempted code:

StringBuilder sb = new StringBuilder("(dog)(cat)(mouse)");

for (int i = 0; i < sb.length(); i ++)
{
   if (sb.charAt(i) == ')')
   {
      sb.insert(i, ' ');
   }
}

String result = sb.toString();

But I'm getting some sort of "Java heap space" error

Upvotes: 1

Views: 7377

Answers (4)

mk.
mk.

Reputation: 11710

You could try:

String string = "(dog)(cat)(mouse)";
string = string.replace(")(", ") (");

This replaces all occurrences of ")(" with ") (".

But if you want to do it your way, the fix will be to increment i using i++; right before you insert, since you are inserting a space before your bracket, not after it.

Upvotes: 5

Kevvvvyp
Kevvvvyp

Reputation: 1774

I've added the space after the bracket (i+1). The reason for the heap error was that you were increasing the length of sb overtime you did an insert.

public static void main(String[] args) {
    StringBuilder sb = new StringBuilder("(dog)(cat)(mouse)");
    int length =  sb.length();

    for (int i = 0; i < length; i ++)
    {
       if (sb.charAt(i) == ')')
       {
         sb.insert(i+1, " ");
       }
    }

    String result = sb.toString();
    System.out.println(result);
}

Upvotes: 0

MadProgrammer
MadProgrammer

Reputation: 347214

So, basically, when the loop encounters the first ) character, it inserts a space at the exact position of i (where the ) currently is), this effectively adds the space BEFORE the ) character.

On the next loop, it will encounter the same ) character and the process repeats until you run out of memory...

Instead, you want to use i + 1 to insert the space AFTER the ) character, for example...

    StringBuilder sb = new StringBuilder("(dog)(cat)(mouse)");

    for (int i = 0; i < sb.length(); i++) {
        if (sb.charAt(i) == ')') {
            sb.insert(i + 1, ' ');
        }
    }

    String result = sb.toString().trim();
    System.out.println(result);

Which outputs

(dog) (cat) (mouse)

Upvotes: 1

Sotirios Delimanolis
Sotirios Delimanolis

Reputation: 279970

(dog)(ca
01234567

You invoke 

  sb.insert(i, ' ');

with i == 4. insert takes everything at the current offset shifts it right by 1 and inserts the given characters. So

(dog )(ca
012345678

Then you loop again, and now i++ becomes 5, where there is the previous ), so you do the same thing and add a space before it. 

(dog  )(ca
0123456789

You keep repeating this until you run out of heap space.

Add the space after the ).

 sb.insert(i + 1, ' ');

Upvotes: 2

Related Questions