DIM a(3, 3)
FOR i = 1 TO 3
FOR j = 1 TO 3
INPUT "element ", a(i, j)
NEXT
NEXT
FOR i = 2 TO 3
FOR j = 1 TO 3
IF a(i, j) > 0 THEN a(i, j) = 2 * a(i, j)
NEXT
NEXT
FOR i = 1 TO 3
FOR j = 1 TO 3
PRINT , a(i, j)
NEXT
NEXT
Тестирование выполнено в программе QB64 ( Скачать )