Need help with a few javabats

[Energizer100]

hi, i need help with a couple of javabats.

1) http://javabat.com/prob?id=String3.sumNumbers

public int sumNumbers(String str) {
 
  String retString = "";
  String m = "";
  int temp = 0;
 
  for (int k = 0; k < str.length(); k++)
    {
      char c = str.charAt(k);
      if (Character.isLetterOrDigit(c))
    {
      retString += c;
    }
    }
 
  for (int i = 0; i < str.length(); i++)
     {
         m = str.charAt(i);
 
         if (Character.isDigit(m))
           {
              temp += m;
           }
     }
 
  return temp;
}
 

2) http://javabat.com/prob?id=Array3.canBalance

public boolean canBalance(int[] nums) {
 
int temp = 0;
 
for (int i = 0; i < nums.length; i++)
{
temp += nums[i];
}
 
if (temp % 2 == 0)
{
return true;
}
else
{
return false;
}
 
}
 

3) http://www.javabat.com/prob?id=String3.sameEnds

4) http://javabat.com/prob?id=Array3.squareUp

As you can see, I need help...thanks

[BigDaddyLH]

I'm just looking at the first exercise -- sumNumbers. your code seems rather random, like you copied it from an earlier exercise. First you copy letters and digits to a second string (why?) and do nothing with the resulting string, then you seem to be summing up the digits in the original string. Take a look at one of the examples:

sumNumbers("aa11b33") → 44

If you summed the digits it would be 1 + 1 + 3 + 3 = 8, not 11 + 33 = 44.

I suggest you start with pseudo code -- how you you describe the solution to this operation in simple steps?

[Energizer100]

I'm just looking at the first exercise -- sumNumbers. your code seems rather random, like you copied it from an earlier exercise. First you copy letters and digits to a second string (why?) and do nothing with the resulting string, then you seem to be summing up the digits in the original string. Take a look at one of the examples:

sumNumbers("aa11b33") → 44

If you summed the digits it would be 1 + 1 + 3 + 3 = 8, not 11 + 33 = 44.

I suggest you start with pseudo code -- how you you describe the solution to this operation in simple steps?

yeah, i forgot to put ret string in the other method. For a string like "7 11", it has a space in it, so I want to condense it. Yeah, i see what u mean.

First I would check each char and see whether or not it is a int. then i have to do something ot check whether or not it is a double digit or a single digit, im having some trouble there

[BigDaddyLH]

First I would check each char and see whether or not it is a int. then i have to do something ot check whether or not it is a double digit or a single digit, im having some trouble there

Triple digits, quadruple digits, ... "Hello123World4567Example"

keep thinking about it until your proposed solution is clearer to you.

[Energizer100]

Triple digits, quadruple digits, ... "Hello123World4567Example"

keep thinking about it until your proposed solution is clearer to you.

I check whether or not there are spaces to the left and to the right of it, if there is, its a single digit and i keep checking to get the entire number, or I can check if there is a letter to the left or to the right of it

[BigDaddyLH]

I check whether or not there are spaces to the left and to the right of it, if there is, its a single digit and i keep checking to get the entire number, or I can check if there is a letter to the left or to the right of it

Why distinguish between a space and a letter? Isn't the key distinction digit or
not a digit?

[Energizer100]

Why distinguish between a space and a letter? Isn't the key distinction digit or
not a digit?

yeah. i got that. what about the rset?

[BigDaddyLH]

yeah. i got that. what about the rset?

It's hard to say, based on what you posted. Suppose the input is:

"a123bc45d678"

Imagine doing this exercise not in Java but in your head, making one pass through the string -- as if someone is reading the characters to you one at a time:

a
1
2
3
b
c
4
5
d
6
7
8

How would you do it? Translate that into Java. Here's what would go through my mind:

a -- looking for start of number
1 -- number started, so far "1"
2 -- another digit, so far "12"
3 -- another digit, so far "123"
b -- number ended, number was 123, total so far 123
c -- looking for start of number
4 -- number started, so far "4"
5 -- another digit, so far "45"
d -- number ended, number was 45, total so far 123+45 = 168
6 -- number started, so far "6"
7 -- another digit, so far "67"
8 -- another digit, so far "678"
--end of input, number as 678, total so far 168+678 = 846

[Energizer100]

It's hard to say, based on what you posted. Suppose the input is:

"a123bc45d678"

Imagine doing this exercise not in Java but in your head, making one pass through the string -- as if someone is reading the characters to you one at a time:

a
1
2
3
b
c
4
5
d
6
7
8

How would you do it? Translate that into Java. Here's what would go through my mind:

a -- looking for start of number
1 -- number started, so far "1"
2 -- another digit, so far "12"
3 -- another digit, so far "123"
b -- number ended, number was 123, total so far 123
c -- looking for start of number
4 -- number started, so far "4"
5 -- another digit, so far "45"
d -- number ended, number was 45, total so far 123+45 = 168
6 -- number started, so far "6"
7 -- another digit, so far "67"
8 -- another digit, so far "678"
--end of input, number as 678, total so far 168+678 = 846

Yeah, I did it like that. It works. Thanks

[bharathk26]

[ spoonfeeding code deleted ]

Please don't just dump code to a question here. We don't supply boiler plate code.
Read the forum guidelines (select 'Help' near the top right of this page).

kind regards,

Jos (moderator)

[JosAH]

@OP: I previously let go of it, but now I have to know: what is a 'Javabat'?

kind regards,

Jos