Найти среднее значение положительных элементов на главной диагонали — QBasic(Бейсик)

'   Nasha matritsa
DATA 82,36,97,53
DATA 55,32,34,28
DATA 84,94,40,95
DATA -63,-71,-93,-94
'   Programma
CLS ' Ochistim ekran
DIM M(4, 4) ' Zavedyom massiv
'   iy - nomer stroki, ix - nomer stolbtsa
'   Zapolnim massiv v tsikle i vivedem matiritsu na ekran
FOR iy = 1 TO 4: FOR ix = 1 TO 4
        READ M(ix, iy) ' Chitaem element iz DATA v massiv
        PRINT M(ix, iy); ' Pechataem element na ekran
NEXT: PRINT: NEXT ' Mezhdu NEXT'ov perevod stroki
'   Cumma otrits. el. pod diagonalyu.
FOR iy = 1 TO 4: FOR ix = 1 TO 4
        IF iy > ix AND M(ix, iy) < 0 THEN Sum = Sum + M(ix, iy)
NEXT: NEXT
' Vivodim rezultat
PRINT "Summa elem. nizhe diagonali:"; Sum
'   Srednee arifmeticheskoe el-tov diagonali
Sr = M(1, 1) ' Pervii element v summu
FOR i = 2 TO 4: Sr = Sr + M(i, i): NEXT ' Ostalnie elementi
' Vivodim rezultat
PRINT "Srednee zn. elem. diagonali:"; Sr / 4