Files
why3/examples/python/mult.py
2021-02-05 20:01:48 +01:00

29 lines
404 B
Python

print("la multiplication dite russe")
a = int(input("entrez a : "))
b = int(input("entrez b : "))
p = a
q = b
if q < 0:
p = -a
q = -b
#@ assert q >= 0
r = 0
while q > 0:
#@ invariant 0 <= q
#@ invariant r + p * q == a * b
#@ variant q
print(p, q, r)
if q % 2 == 1:
r = r + p
p = p + p
q = q // 2
print(p, q, r)
print("a * b =", r)
#@ assert r == a * b