Programming Forums > Application Development > Java

xavier · Dec 12th, 2004, 4:30 AM

c1="1234"
c2="123456" those are both char arrays.
I want to make them eqwals in elngth :

c1="001234"
c2="123456"

Like that, inserting '0' in the first array......Now, i dont know wich array is shortest. I've tried it like this:
int N=c1.length;
int M=c2.length;

(Toggle Plain Text)

while(N!=M){
 if(N<M){
 	for(int j=N;j>=1;j--)
 	c1[j]=c1[j-1];
 	c1[0]='0';
            N++;
 }
 if(N>M){
 	for(int k=M;k>=1;k--)
 	c2[k]=c2[k-1];
 	c2[0]='0';
 	M++;
 }
	}

It gives IndexOutOfBounds at: c1[j]=c1[j-1]; or c2[k]=c2[k-1]
I don't realy undersand y.

Also i don't want to copy the shortest array into a new one and inserting the zeros there ...
It's a simple problem .. but i just can't find an answere.
HELP

andersRson · Dec 12th, 2004, 5:05 AM

The reason is that you are accessing the array index N or M, which doesn't exist. There are N and M elements in the arrays, indexed from 0 to N - 1 and M - 1. So there is no element at c1[N] and c2[M], the arrays end at c1[N - 1] and c2[M - 1].
You cannot just index out of the array and expect it to grow magically, the size is fixed at the arrays creation. You will have to create new arrays and copy the contents of the old ones into the new ones.

xavier · Dec 12th, 2004, 5:25 AM

Ok, thanks for the info

ZenMasterJG · Dec 12th, 2004, 2:39 PM

If you want it to grow magically, use a Vector. (Or an arraylist, i think, im not hip to a bunch of the new Java 5 weirdness)

Dec 12th, 2004, 4:30 AM	#1
xavier Professional Programmer Join Date: Oct 2004 Location: .ro Posts: 383 Rep Power: 4	c1="1234" c2="123456" those are both char arrays. I want to make them eqwals in elngth : c1="001234" c2="123456" Like that, inserting '0' in the first array......Now, i dont know wich array is shortest. I've tried it like this: int N=c1.length; int M=c2.length; (Toggle Plain Text) while(N!=M){ if(N<M){ for(int j=N;j>=1;j--) c1[j]=c1[j-1]; c1[0]='0'; N++; } if(N>M){ for(int k=M;k>=1;k--) c2[k]=c2[k-1]; c2[0]='0'; M++; } } while(N!=M){ if(N<M){ for(int j=N;j>=1;j--) c1[j]=c1[j-1]; c1[0]='0'; N++; } if(N>M){ for(int k=M;k>=1;k--) c2[k]=c2[k-1]; c2[0]='0'; M++; } } It gives IndexOutOfBounds at: c1[j]=c1[j-1]; or c2[k]=c2[k-1] I don't realy undersand y. Also i don't want to copy the shortest array into a new one and inserting the zeros there ... It's a simple problem .. but i just can't find an answere. HELP __________________ Don't take life too seriously, it's not permanent !

Dec 12th, 2004, 5:25 AM	#3
xavier Professional Programmer Join Date: Oct 2004 Location: .ro Posts: 383 Rep Power: 4	Ok, thanks for the info __________________ Don't take life too seriously, it's not permanent !

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Dec 12th, 2004, 5:05 AM	#2
andersRson Newbie Join Date: Nov 2004 Posts: 16 Rep Power: 0	The reason is that you are accessing the array index N or M, which doesn't exist. There are N and M elements in the arrays, indexed from 0 to N - 1 and M - 1. So there is no element at c1[N] and c2[M], the arrays end at c1[N - 1] and c2[M - 1]. You cannot just index out of the array and expect it to grow magically, the size is fixed at the arrays creation. You will have to create new arrays and copy the contents of the old ones into the new ones.

Dec 12th, 2004, 2:39 PM	#4
ZenMasterJG Hobbyist Programmer Join Date: Nov 2004 Location: Boston, MA Posts: 148 Rep Power: 4	If you want it to grow magically, use a Vector. (Or an arraylist, i think, im not hip to a bunch of the new Java 5 weirdness)

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Programming Forums > Application Development > Java

Insertig An Element