The program:

! Produces a 3x3 matrix with 0 for all elements

! except where row=column, and prints them out.

! do trace, slow (row,column, Identity )

DIM Identity (1 to 3, 1 to 3)

FOR row = 1 to 3

FOR column = 1 to 3

IF row = column then

LET Identity (row,column)=1

ELSE

LET Identity (row,column)=0

END IF

NEXT column

NEXT row

PRINT

FOR row = 1 to 3

FOR column = 1 to 3

PRINT Identity (row,column);

NEXT column

PRINT

NEXT row

SOUND 1000,.1

PAUSE 4

END

The output:

1 0 0

0 1 0

0 0 1

Now put the code into PP8.1