# Thread: Error in inverted Pascal triangle program

1. Member Join Date
Nov 2012
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## Error in inverted Pascal triangle program

Hi everyone. I don´t know why the following error appears when I try to execute my program, so if anyone can help me please... xD
Source code:
import java.util.*;

public class pascal2 {

public static void main(String[] args) {

Scanner in = new Scanner(System.in);
int x = 0;

do {
System.out.print("How many values (1...13) ?");
x = in.nextInt();
} while ( x<1 || x>13 );

int y = (x*2)-1;
int [] a = new int [y];
int [][] b = new int [y][x];
int j = (x-1);
int k = y;

for ( x = 0 ; x <= j ; x++ ) {
for ( y = 0 ; y < k ; y++ ) {
if ( x == 0 ) {
if ( y == (((k+1)/2)-1) ) b[y][x] = 1;
else b[y][x] = 0;
}
else {
if ( y == 0 ) b[y][x] = b[y+1][x-1];
else {
if ( y == (k-1) ) b[y][x] = b[y-1][x-1];
else b[y][x] = b[y-1][x-1] + b[y+1][x-1];
}
}
}
}
for ( x = j ; x >= 0 ; x-- ) {
for ( y = 0 ; y <= k ; y++ ) {
if ( y == (k-1) ) {
if ( b[y][x] == 0 ) System.out.println(" ");
else System.out.println( b[y][x] );
}
else {
if ( b[y][x] == 0 ) System.out.print(" "); <-- line 43
else System.out.print( b[y][x] );
}
}
}
}
}

Error in cmd:
D:\>java pascal2
How many values (1...13) ?7
1 6 15 20 15 6 1
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 13
at pascal2.main(pascal2.java:43)
Last edited by darkwolf1345; 11-15-2012 at 05:41 PM.  Reply With Quote

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## Re: Error in inverted Pascal triangle program

Please use [code] tags [/code] when posting code.

I'm guessing here (as I don't read unformatted code), but you are accessing someArray where someArray is only 13 elements long.
Arrays go from 0 to (arrayLength - 1).  Reply With Quote

3. Member Join Date
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## Re: Error in inverted Pascal triangle program

I fixed it, thanks a lot (I knew arrays go from 0 to lenght-1, but you helped me remind it xD )

I didnt understand "
Java Code:
` tags`
", can you explain it some other way? because I dont want to botter anyone else with that, and I was hoping you could help me fix the spaces, because when the user selects a number of lines that contain numbers with more than one digit, the spaces go all wrong... and for you to help me you need to read the code xDDD  Reply With Quote

4. ## Re: Error in inverted Pascal triangle program

Guide For New Members  Reply With Quote