End of 2d array

Question

how can i say in java

if i get to the end of a row in a 2d array and i have only encountered 0's in that row to set row to the next one (row ++) and set column to 0 (column = 0)?

i am having problems where my algorithm i going in to an infinite loop :D

thanks

Answer 1

uh, sounds like you want a basic nested loop to iterate across your array...

for(int i=0; i<rows.length; i++)
   for(int j=0; j<columns.length; j++)

This will reset your columns regardless. If you want to do something tricksy and hackish

int sum =0;
for(int i=0; i<rows.length; i++)
{
  sum+= rows[i];
  if(i == rows.length-1 && sum == 0)
  {
     i=i+1
  } 
   for(int j=0; j<columns.length; j++)
   {
     //whatever else you want here
   }
}

Note that this seems like a most unusual condition algorithmically...I hope you're not trying to hack around a dirty bug instead of figuring out what the real problem is!

Answer 2

This sample loops through the array until the first non-zero value is found and outputs it along with the coordinates.

int[][] x = new int[column][row];
boolean allzero = true;

for(int i=0;i<row;i++) {
  for(int j=0;j<column;j++) {
    allzero = (x[j][i]==0) && allzero;
    if(!allzero) {
      //what do we want to do when we encounter a non zero value?
      System.out.println("Found "+x[j][i]+" at row: "+i+" column: "+j);
      break;
    }
  }
  if(!allzero) {
    //what do we want to do when we encountered a non zero value?
    break;
  }
}

Actually I don't understand what you mean with

set column to 0 (column = 0)

If you just want to continue looping through the array two nested for-loops like the above will do it. After one row is finished (inner-loop) the outer-loop increments by one and the inner-loop restarts at zero. Thus all rows are run through from start to end.