[SOLVED] String out of bound error

[maxb]

Hi,

Everytime I try to input a string longer than one char I get a string out of bound error... and I'm trying to figure out why.

here my code (basically it a method that checks if a sting has char placed in order)
_________________________

import java.io.*;
import java.util.*;

public class Alpha{

public static boolean charEnOrdreAlpha (String chaine) {

int test = 0;

if (chaine.length() <= 1){//1
return true;
}//1

else {//2

chaine = chaine.toLowerCase();

for (int i=0; i< chaine.length() ; i++){//3


char lettre1 = chaine.charAt (i);
char lettre2 = chaine.charAt (i+1);

if (lettre1 < lettre2) {//4
test = 0;



} else {//5
test = 1;
}//5

}//3
}
if (test == 0) {
return false;
}
else {
return true;
}
}//2


}

___________________

thanks in advance

[CJSLMAN]

• Need to change the following if statement:

if (chaine.length() <= 1)

It works as is, but anything less than 1 is zero, which means that it doesn't exist... better make it:

if (chaine.length() == 1)

• This is probably were your problem is:

for (int i=0; i< chaine.length() ; i++){//3
char lettre1 = chaine.charAt (i);
char lettre2 = chaine.charAt (i+1);
.
.
.

To fix it, either:

• drop the for loop and assign the lettre1/lettre2 variable directly like you are now or...
• keep the for loop and put the chars in a two element array.

Why are you receiving the out of bound error? Because on the the second loop, chaine.charAt (i+1) is trying to get the third char of a two char string... no can do.

Luck,
CJSL

[maxb]

Why are you receiving the out of bound error? Because on the the second loop, chaine.charAt (i+1) is trying to get the third char of a two char string... no can do.

Luck,
CJSL

I don't understand what you mean. First I want to compare the first char with the second one. Like compare a to b in "abc". After I need to do the same with b and c. Why (i+1) which at the beginning is supposed to be (0+1) than second position char is returning an error???

[CJSLMAN]

ok... like Jack The Ripper said "Let's do this piece by piece"...

Let's say chaine = "my"

The for statement is going to do two loops (i=0, i=1):
Loop #1:
i=0
lettre1 = 'm', because charAt (i) = 'm'
lettre2 = 'y', because charAt (i+1) = 'y'

Loop #2:
i=1
lettre1 = 'y', because charAt (i) = 'y'
lettre2 = '???', because charAt (i+1) = '???' <-out of bounds

Looking at this again, another solution might be to change the for comparation from "i<chaine.length()" to "i<chaine.length()-1".

Luck,
CJSL

[maxb]

I finally managed to solve the problem. Thanks for your help

public class Alpha{

public static boolean charEnOrdreAlpha (String chaine) {

int test = 0;//initialisé à 0 de façon à ce que le test passe par défault
int test2 = 0;//initialisé à 0 de façon à ce que le test passe par défault

if (chaine.length() <= 1){//1 cas ou la chaine serait de 1 ou 0 caractère.
return true;
}//1

else {//2

chaine = chaine.toLowerCase(); //transforme le tout en minuscules


for (int i=0; i< chaine.length()-1 ; i++){//3 boucle qui incrémente le i afin de comparaison


char lettre1 = chaine.charAt (i);
char lettre2 = chaine.charAt (i+1);

if (lettre1 <= lettre2) {//4
test2 = 0;



} else {//5
test = 1;// on met test2 à 1 dès que l'ordre alpha n'est pas respectée
}//5

}//3
}//2

if (test == 0 && test2 == 0) {//si dans aucun cas l'ordre alpha n'est pas respectée
return true;
}
else {
return false;
}

}//fin méthode
}//fin classe