Java runtime error: String index out of range.

[whatson]

I've written a program that displays tokens dropped into a board depending on the user's selection of which column to drop it in. I'm getting a runtime error

java.lang.StringIndexOutOfBoundsExcepti… String index out of range: 42
at java.lang.String.substring(Unknown Source)
at A1Program.extractRow(A1Program.java:83)
at A1Program.start(A1Program.java:19)
at A1Application.main(A1Application.java:11…
at sun.reflect.NativeMethodAccessorImpl.inv… Method)
at sun.reflect.NativeMethodAccessorImpl.inv… Source)
at sun.reflect.DelegatingMethodAccessorImpl… Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at edu.rice.cs.drjava.model.compiler.JavacC…
when I run the program, and I'm a bit lost as to where I might have gone wrong.

My code is:

public class A1Program {

public void start() {

String inputString = " ";
boolean gameOver = false;

String tokens = inputString;

while (!gameOver) {
int column = columnResult();
tokens = enterToken("X", tokens, column);
System.out.println(tokens);
displayBoard(extractRow(5, tokens));
displayBoard(extractRow(4, tokens));
displayBoard(extractRow(3, tokens));
displayBoard(extractRow(2, tokens));
displayBoard(extractRow(1, tokens));
displayBoard(extractRow(0, tokens));
System.out.println("---------------");
}
}

private int columnResult(){
System.out.println("Enter column for X:");
String keyInput = Keyboard.readInput();
int column1 = Integer.parseInt(keyInput);
return column1;
}
private String enterToken(String tokenSymbol, String inputString, int column){
String columnEdit = inputString.substring(column*6-6,column*…

String columnEdit1 = columnEdit.trim();
String columnEdit2 = columnEdit1+tokenSymbol+" ";
String columnEdit3 = columnEdit2.substring(0,6);
String start = inputString.substring(0,column*6-6);
String end = inputString.substring(column*6);

System.out.println(start);
return start+tokenSymbol+end;
}

private String extractRow(int row, String tokens) {
String rowString1 = tokens.substring(row, row + 1);
String rowString2 = tokens.substring(row + 6, row + 7);
String rowString3 = tokens.substring(row + 12, row + 13);
String rowString4 = tokens.substring(row + 18, row + 19);
String rowString5 = tokens.substring(row + 24, row + 25);
String rowString6 = tokens.substring(row + 30, row + 31);
String rowString7 = tokens.substring(row + 36, row + 37);

return "|" + rowString1 + "|" + rowString2 + "|"
+ rowString3 + "|" + rowString4 + "|" + rowString5
+ "|" + rowString6 + "|" + rowString7 + "|";

}

private void displayBoard(String extractRow) {

System.out.println(extractRow);

}
}

Any help is appreciated!

[Fubarable]

Can you show us which line is causing the error? Also please try to edit your post above and place [code] [/code] tags above and below your posted code to help make it retain its formatting and be readable.

[Fubarable]

.... or not ...

[Junky]

String rowString2 = tokens.substring(row + 6, row + 7);
String rowString3 = tokens.substring(row + 12, row + 13);
String rowString4 = tokens.substring(row + 18, row + 19);
String rowString5 = tokens.substring(row + 24, row + 25);
String rowString6 = tokens.substring(row + 30, row + 31);
String rowString7 = tokens.substring(row + 36, row + 37);

It almost inevitable that you get SIOOBE when you see lines of code like. It is dicfficult to guarantee that all Strings are going to be long enough that x + 37 will still be in bounds.

[DarrylBurke]

.... or not ...

Probably not.

Cross posted
Java method arrangement, runtime error - Stack Overflow
Help with Java task please (method arrangement)? - Yahoo! Answers

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