I have to create an exercise to find the largest prime number after being given a certain value using the while function, what is wrong with what I created below ??
def maior_primo(n):
x=0
y=0
while y<=n:
y=y+1
x=n-1
if (x % y==0 and x//y==0):
return x
else:
x%y!=0
return y
There are some problems with your solution. The increment in the cycle was being done right at the beginning so I would analyze one more element in:
while y<=n:
y=y+1
To know if a number is prime we have to try to divide by all that are in the middle and not only one, as it happens here:
if (x % y==0 and x//y==0):
return x
Extending your solution and making it right:
def maior_primo(n):
x=0
y=n #começar do cima para baixo para poder sair no primeiro primo
while y>=1: #ciclo agora ao contrario até 1
for x in range(2, y + 1): #range nao inclui o ultimo, logo tem de ser y +1
if y % x == 0:
break
if x == y: #se chegou até y é porque nao deu para dividir por nenhum, logo primo
return x
y = y - 1
return 1 #se nao deu para achar nenhum primo retorna-se um