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Dynamic use of arrays
Arrays example from a Well House Consultants training course
More on Arrays [link]
Source code: rowby.java Module: J705
/* See http://www.wellho.net/mouth/1498_.html for details Although you cannot extend an array in Java (but you can in java.lang.util objects such as a Vector and an ArrayList) you can re-allocate a new array to an existing name. */ public class rowby { public static void main (String [] args) { /* Pascal's Triangle - row by row using previous and current rows in arrays of those names */ int rows = 15; int [] previous, current; previous = new int[0]; for (int k=0; k<rows; k++) { // Calculate current row based on previous one current = new int[previous.length+1]; current[k]= current[0] = 1; for (int j=1; j<previous.length; j++) { current[j] = previous[j-1] + previous[j]; } // Output the current row for (int c=0; c<current.length; c++) { System.out.print(current[c]); System.out.print(" "); } System.out.println(); // Make the current row into the previous one previous = current; } } } /* Sample output: [trainee@snowdrop java08]$ java rowby 1 1 1 1 2 1 1 3 3 1 1 4 6 4 1 1 5 10 10 5 1 1 6 15 20 15 6 1 1 7 21 35 35 21 7 1 1 8 28 56 70 56 28 8 1 1 9 36 84 126 126 84 36 9 1 1 10 45 120 210 252 210 120 45 10 1 1 11 55 165 330 462 462 330 165 55 11 1 1 12 66 220 495 792 924 792 495 220 66 12 1 1 13 78 286 715 1287 1716 1716 1287 715 286 78 13 1 1 14 91 364 1001 2002 3003 3432 3003 2002 1001 364 91 14 1 [trainee@snowdrop java08]$ */ Learn about this subject
This module and example are covered on the following public courses:
* Learning to Program in Java * Java Bootcamp * Java Programming for the Web Also available on on site courses for larger groups Books covering this topic
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Other Examples
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other closely related examples on the "Arrays" module index page.
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