Thread: Making a method to move blocks in a grid

Again it looks like you are trying to write code. Where are the steps for #4?
I'd expect something like this:

begin loop to work on a row
do things needed for this row
begin loop to work on the columns for this row
compute location for next shape
get color for next shape
create shape using color and location
save shape in list
end loop for columns this row
end loop for rows

 
public static java.util.List<acm.graphics.GRect> createPlayfield()
{
     Random r = new Random();
     List<GRect> l = null;
     int x = 0;
     int y = ROWZERO - BLOCKHEIGHT;
     Color c = new Color(r.nextInt(256),r.nextInt(256),r.nextInt(256));
 
     for (i = 0; i <= BLOCKROWS; i++) // is this part of grid?
     {
        i = i * ROWSEPARATION + ROWZERO;
          for (j = 0; j <= NBLOCKS; j++) // is this part of grid?
          {
             j = j * BLOCKWIDTH;
             addBrick(l,l.getX(),l.getY(),BLOCKWIDTH,BLOCKHEIGHT,l.getColor());
          } 
      }
        return l;
}

The problem now is that the i and j are just there, they aren't doing anything because I didn't set anything to it, and there is no grid because I have to put BLOCKROWS x NBLOCK or is that described in the for loop

now is that the i and j are just there, they aren't doing anything

Do they keep track of the row and column?

That would be how you would use the loops (see post#26). Outer loop for rows, inner loop for columns.

Can you say in words what the code you posted is supposed to do?

Sometimes there is nothing to be done. The comment: "do things for this ..." was just a reminder and a place holder in case there was something.

What is the purpose of that code?

You're mixing two things together. One variable needs to keep track of the row (or column) and the other needs to be used to locate the shape's x (and y) location on the grid. The x and y values are computed using the row and column values.

I'm lost, have no Idea about what to do with that code

Finish the steps in the design first before working on the code.
Take a piece of paper and draw the shapes on it as they are supposed to go in the grid.
Label the locations of each shape using the values/variables given in the assignment statement.

Where is ROWZERO? How is ROWSEPARATION used.

Again you are mixing the row and column values with the x and y locations for the shapes.

Can you now put together the detailed simple steps for step#4?

i and j are put on a grid, j depends on i, so..

for i
for j
do i * j? still not sure

and then put into the list?

I'm asking for the steps in English (pseudo code) that the program needs to do for step#4.

where do you compute the x and y values for the locations of the shapes?
Where is the color created?

What are the last two steps for?

for every i equal to 0 to BLOCKROWS
for every j equal to 0 to NBLOCKS
perform addbrick
perform i added to j
add (i added to j) to location of list

for every i equal to 0 to BLOCKROWS
for every j equal to 0 to NBLOCKS
create x and y to compute location
create colour
perform addbrick
create i
create j
perform i * j
add (i * j) to list
return the list

You'll need the x & y for addbrick()

What are the last two steps for?

Why are you writing code before finishing the design?

6) and 7) and computed together and added to the list?