If the column size in the arrays are in zig-zag form means not fixed for every row than variable size array is useful.
Syntax to declare variable size array
int x[][] = new int [3][]; x[0] = new int [2]; x[1] = new int [4]; x[2] = new int [3];
Example 1: Write a program in Java to input 3 student marks using variable size array.
package variablesizearray; import java.util.Scanner; public class Variablesizearray { public static void main(String[] args) { int i, j; int a[][] = new int [3][]; a[0] = new int[3]; a[1] = new int[5]; a[2] = new int[4]; Scanner scan = new Scanner(System.in); for(i=0;i<=2;i++) //row { System.out.println("Enter " + (i+1) + " student marks"); for(j=0;j<a[i].length;j++) //col { a[i][j] = scan.nextInt(); } } for(i=0;i<=2;i++) { System.out.println((i+1) + " student marks is: "); for(j=0;j<a[i].length;j++) //col { System.out.print(a[i][j]); } System.out.println("\n"); } } }