首先,如果您想不断检查输入,则必须使用循环。如在其中,该算法的suedocode应该为:
Loop Begin
Check the value of a and b
If a or b is less than 0 then ask for input again
Otherwise, continue
请注意,该算法 有 跑步 至少 一次。
这基本上就是伪模 应该 看起来像。因此,在这种情况下,您可以使用 do-while
循环结构。在Python,没有类似的东西,所以我们 仿真 它:
import math
def take_in():
a = raw_input("Enter the value of side a -> ")
b = raw_input("Enter the value of side b -> ")
# Trying to convert to a float
try:
a, b = float(a), float(b)
# If successfully converted, then we return
if a > 0 and b > 0:
return a, b
except ValueError:
pass
# If we cannot return, then we return false, with a nice comment
print "Invalid input"
return False
def main():
# Calling the function at least once
valid = take_in()
# While we are not getting valid input, we keep calling the function
while not valid:
# Assigning the value to valid
valid = take_in()
# Breaking the return tuple into a and b
a, b = valid
print math.sqrt(a ** 2 + b ** 2)
if __name__ == '__main__':
main()