Μετατρέψτε την for σε ισοδύναμη while
for i in range(20,40,10):
print i
i=20
while i>40:
i=i+10
while i<40:
while i<40
i=10
while i<20:
i=i+40
for i in range(20,40,-10):
i=i-10
for i in range(3,13):
i=13
while i<3:
i=i+1
i=3
while i<13:
while i>13:
for i in range(10,5,-5):
while i>5:
i=i+5
i=i-5
while i<5:
for i in range(10):
while i<0:
i=0
while i>10:
while i<10:
for i in range(12,10,-1):
i=12
i=i-1