100 PROGRAM "Identity.bas"
110 INPUT PROMPT "Enter size of matrix: ":N
120 NUMERIC A(1 TO N,1 TO N)
130 CALL INIT(A)
140 CALL WRITE(A)
150 DEF INIT(REF T)
160   FOR I=LBOUND(T,1) TO UBOUND(T,1)
170     FOR J=LBOUND(T,2) TO UBOUND(T,2)
180       LET T(I,J)=0
190     NEXT
200     LET T(I,I)=1
210   NEXT
220 END DEF
230 DEF WRITE(REF T)
240   FOR I=LBOUND(T,1) TO UBOUND(T,1)
250     FOR J=LBOUND(T,2) TO UBOUND(T,2)
260       PRINT T(I,J);
270     NEXT
280     PRINT
290   NEXT
300 END DEF