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