Help needed with string manipulation

[stringkilla]

This is what i have so far: and im at a loss of what to do next. spent hours and hours so far and am getting over it. please post helpful meaning code with explanations as i dont know much and am new to this world of programming.

Thanks heaps.


String input;
String output;
char current;


System.out.println ("Enter a sentence:");
input = scan.nextLine();
current = input.charAt(0);
if (current == 'a')
output = output + current;
System.out.println ("+output");




}
}

[gafa]

What exactly task you feel problematic?
Is there any error?

[stringkilla]

firstly,

output = output + current;

is causing error. i want to add each individual char to output string one at a time.

[Zack]

When you get errors, please post the full error message.

In this case, the error is because output is not initialized; that is, you did not give it an initial value. Therefore, you cannot concatenate to it.

Try replacing this:

String output;

...with this:

String output = "";

This assignment looks quite fun actually, best of luck on it.

[stringkilla]

thanks very much, ill try and get back to you.

[stringkilla]

g'day again,

program is doing what i want it to do thus far. now i just need to implement some more specific code to complete the task.

this is what i have so far: (which compiles and runs correctly)



String input;
String output = "";
char current;
int charactar;

System.out.println ("Enter a sentence:");
input = scan.nextLine();
current = input.charAt(0);
if (current == 'a')
output = output + current;
System.out.println ("Content:"+output);


}
}

after the if statement is performed, can i then loop it back around to do the if statement again for the charAt(1), then charAt(2) and so on? if so please show me.

thanks

[JosAH]

after the if statement is performed, can i then loop it back around to do the if statement again for the charAt(1), then charAt(2) and so on? if so please show me.

You already mentioned it yourself: a loop; it would surprise me if your textbook doesn't explain those in great detail. Do some research first.

kind regards,

Jos

[stringkilla]

ok so i know how to do while loops sort of but how do i implement:

input.charAt(from 1'st to last character of string) ???

instead of doing input.charAt(0) (1) (2)... and so on

is it something like:
int length;
get the length of string (e.g. 25 characters)
length = input.length()
then going:

while (input.charAt(o) < 25)

or something

help :(

thanks

[Norm]

how do i implement:

input.charAt(from 1'st to last character of string) ???

Use a for loop with the index starting at 0(the first char) to the last char(index is length of string -1)
Use the loop index variable(for example i) as the arg to the charAt(i) method.

If you use a while loop, you will have to do all the index handling your self: Initialize, test and increment that is easily done by a for loop

[stringkilla]

sorry norm but that did not help me. rethink you reply to my previous post taking into account the assignment question and the relevance of your answer. i am asking for the answer. or some small portion of code that will help my program so far. have a look at what ive done. im stuck here. can you help me in the way i want you to and add to this.

thanks.


String input;
String output = "";
char current;
int length;

System.out.println ("Enter a sentence:");
input = scan.nextLine();
length = input.length();
current = input.charAt(0);
for (int length = 0; length <input.length(); length++) // dont know about this but i think im on to something
if (current == 'a')


output = output + current;
System.out.println ("Content:"+output);





be HELPFUL please i do not have your knowledge.

[Fubarable]

sorry norm but that did not help me. rethink you reply to my previous post taking into account the assignment question and the relevance of your answer. i am asking for the answer. or some small portion of code that will help my program so far. have a look at what ive done. im stuck here. can you help me in the way i want you to and add to this.
....
be HELPFUL please i do not have your knowledge.

I beg to differ as Norm was being helpful, very helpful in fact, but the problem is that you didn't understand some or all of his answer, and fortunately this can be fixed. We don't like giving "the answer" here but rather helping you find the answer as you will learn so much more this way. In order for us to help you better, what you may wish to do is to tell us exactly what about his answer you don't understand, and perhaps we can either explain it more fully or else show you a decent tutorial that will help you understand us better.

Best of luck at solving your problem! :)

[Fubarable]

or (int length = 0; length <input.length(); length++) // dont know about this but i think im on to something

Yes, you are on to something here! Have you worked with for loops before? If not, please check out the tutorial on how they are used:
Using for loops

You will want to add an opening and closing brace for this loop and inside use the length int variable, the index of the loop, in your input.charAt(length) method call.

Keep at it and best of luck!

[stringkilla]

ok thanks very much, ill keep going with it and get back to you.

[al_Marshy_1981]

definetely keep posting you are closer than you might think

[stringkilla]

ok so now when running the program i get weird output. please run, type ab or a or aa and see. stumped again. am trying to get it so it will output " a." or "a " or "A ". and so on. but am getting weirdness. any suggestions??? thanks

[JosAH]

if(current == 'a' && current+1 == 'b')

That is silly of course: if current == 'a' of course current+1 equals 'b'; what did you have in mind?

kind regards,

Jos

[stringkilla]

what? this is what i get!?!



Enter a sentence:
aaa
aaaaaa
C:\>

please re-read last post. thanks

[JosAH]

what? this is what i get!?!

[ snip ]

please re-read last post. thanks

I don't need to; that if condition is silly. b.t.w. change your output to:

System.out.print("["+output+"]");

... and you'll see how many times output is printed ...

kind regards,

Jos

[stringkilla]

now i get this:


Enter a sentence:
ab
[a]

Enter a sentence:
a
[a]

Enter a sentence:
aa
[a][aa]

Enter a sentence:
abab
[a][aa]

Enter a sentence:
ab
[a]

i want it to output:"ab"

[JosAH]

now i get this:

C:\KXT101>java AssigOne210
Enter a sentence:
ab
[a]
C:\KXT101>java AssigOne210
Enter a sentence:
a
[a]
C:\KXT101>java AssigOne210
Enter a sentence:
aa
[a][aa]
C:\KXT101>java AssigOne210
Enter a sentence:
abab
[a][aa]
C:\KXT101>java AssigOne210
Enter a sentence:
ab
[a]

i want it to output:"ab"

Your computer can't guess what you want (and neither can we); now if the current character is an 'a' you append it to your output String and print it. If that's not what you want you should change your program code.

kind regards,

Jos