nested for loops with String

Question

I am having problems with this method.

It is a constructor with 2 parameters: a name and a String with 100 char called in. in must be turned in to a array[10][10] with vak(an object) in it.

I always get the same exception:

StringIndexOutOfBoundsException: String index out of range: 100

This is the method:

 public SpelBord(String naam, String in) {
        int muur=1;
        this.naam = naam;
        System.out.println(in.length());
         for(int i=0;i<in.length();i++) {
            for (int j = 0; j < vakken.length; j++) {
                for (int k = 0; k < vakken[j].length; k++) {

                    if (in.charAt(i) == '.') {
                        this.vakken[j][k] = new Vak();

                    }
                    if (in.charAt(i) == 'K') {
                        this.vakken[j][k] = new Vak(false, false, new   Kist());
                    }
                    if (in.charAt(i) == 'D') {
                        this.vakken[j][k] = new Vak(true, false);

                    }
                    if (in.charAt(i) == 'M') {
                        this.vakken[j][k] = new Vak(false, false, new Man());



                    }
                     if (in.charAt(i) == '#') {
                        this.vakken[j][k] = new Vak(false, true);

                    }
                }
            }
        }

I think it is something with the for loops. thank you in advance!

I don't understand why you have the 1st for, it's useless if you have vakken instanciated as new Vak[10][10] — yiabiten
– yiabiten, Commented Apr 13, 2015 at 15:31
could you give more details as to what this code is suppose achieve? Like what is the variable vakken? and why is` i required to in incremented in each if` statement? — Blip
– Blip, Commented Apr 13, 2015 at 15:32
Yes that definately is the cause for your error incrementing i inside the dor loop again as others have suggested — starthis
– starthis, Commented Apr 13, 2015 at 15:36

Md. Nasir Uddin Bhuiyan · Accepted Answer · 2015-04-13 18:05:16Z

1

You got this error StringIndexOutOfBoundsException: String index out of range: 100

Because: Suppose you enter a String of 100 character suppose the string is "ABCDEFGHIJK . . . . . . LMNOPQRSTUVWXYZ" in that case in.length=100 Now see what happens to your code: (Read the comments)

for(int i=0;i<in.length();i++) {// i=0
            for (int j = 0; j < vakken.length; j++) {
                for (int k = 0; k < vakken[j].length; k++) {

                    if (in.charAt(i) == '.') {//looking for charAt(0)
                        this.vakken[j][k] = new Vak();
                i++;//if this condition satisfies i=1
                    }
                    if (in.charAt(i) == 'K') {//if last if condition satisfies looking for charAt(1)
                        this.vakken[j][k] = new Vak(false, false, new Kist());
                i++;//if this condition satisfies i=2
                    }
                    if (in.charAt(i) == 'D') {//if last if condition satisfies looking for charAt(2)
                        this.vakken[j][k] = new Vak(true, false);
                i++;//if this condition satisfies i=3
                    }
                    if (in.charAt(i) == 'M') {//if last if condition satisfies looking for charAt(3)
                        this.vakken[j][k] = new Vak(false, false, new Man());

                                 muur++;
                i++;//if this condition satisfies i=4
                    }
                     if (in.charAt(i) == '#') {//if last if condition satisfies looking for charAt(4)
                        this.vakken[j][k] = new Vak(false, true);
            i++;//if this condition satisfies i=5
                    }
                }
            }

Here, in the code the value of your variable i increasing unnecessarily. Now think that i=99 in the loop. Now see what happens in your code:(Read the comments carefully):

    for(int i=0;i<in.length();i++) {// i=99
                for (int j = 0; j < vakken.length; j++) {
                    for (int k = 0; k < vakken[j].length; k++) {

                        if (in.charAt(i) == '.') {//looking for charAt(99)
                            this.vakken[j][k] = new Vak();
                    i++;//if this condition satisfies i=100
                        }
                        if (in.charAt(i) == 'K') {
                        //if last if condition satisfies 
                        //looking for charAt(100) 
                        //now charAt(100) dose not exists 
                        //and an error occurs that String out of range
                            this.vakken[j][k] = new Vak(false, false, new Kist());
                    i++;
                        }
                        if (in.charAt(i) == 'D') {
                            this.vakken[j][k] = new Vak(true, false);
                    i++;
                        }
                        if (in.charAt(i) == 'M') {
                            this.vakken[j][k] = new Vak(false, false, new Man());

                                     muur++;
                    i++;
                        }
                         if (in.charAt(i) == '#') {
                            this.vakken[j][k] = new Vak(false, true);
                i++;
                        }
                    }
                }

I think you understand why the error StringIndexOutOfBoundsException: String index out of range: 100 occurs.

To improve your code you can use else if ladder and do not increment i unnecessarily because i is increment in your for loop - for(int i=0;i<in.length();i++ . And try to setup/clear the logic before starting coding.

edited Apr 13, 2015 at 18:05

answered Apr 13, 2015 at 15:57

Md. Nasir Uddin Bhuiyan

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16 Comments

Ben Gabriëls Over a year ago

Thank you I understand my mistake. But there is still something not oke. If I set a counter how much time this.vakken[j][k] = new Vak(false, true); it runs. the counter is 3900. I don't know how this can be.. (sorry for my bad sentence construction )

Md. Nasir Uddin Bhuiyan Over a year ago

I couldn't understand your comment (If I set a counter how muth time this.vakken[j][k] = new Vak(false, true);).

Md. Nasir Uddin Bhuiyan Over a year ago

this.vakken[j][k] = new Vak(false, true); It depends on your input String because there is a check [ if (in.charAt(i) == '#') ] . when the character '#' is found in string it executes.

Md. Nasir Uddin Bhuiyan Over a year ago

It's totally depend on your input String.

Ben Gabriëls Over a year ago

Sorry :) if i set this (int muur=0;) in the beginning of the method and than I set this ( '(in.charAt(i) == '#') { this.vakken[j][k] = new Vak(false, true); ++muur; } ') (++muur;) Than at the end of the method I wrote this 'System.out.print(muur);' and when I run it muur = 3900

|

DesirePRG · Accepted Answer · 2015-04-13 16:02:20Z

1

The for loops takes care of incrementing the value of i,j. You do not need to do it again.

 for(int i=0;i<in.length();i++)

i++ will be executed as the final statement before the loop ends. So will j++ and k++ in its respective loops.

answered Apr 13, 2015 at 16:02

DesirePRG

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Comments

Blip · Accepted Answer · 2015-04-13 16:12:55Z

1

I think that you should have continue statements instead of i++ in the if statements. Then you should not be using the j and k loops. Instead of that use local variables j and k initialised to 0 in the i loop. In the if statements increment the k by 1 and check that k is less than 10. If k is equal to 10 reset k to 0 and increment j by 1.

answered Apr 13, 2015 at 16:12

Blip

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