Python提示计算器错误

Question

下面的代码应该运行顺利，但由于某种原因终端告诉我有一个问题。我的问题在最下面。你知道吗

print 'Welcome to Cash Calculator!'

cash = input('How much was the original price of the services or goods you paid for, excluding vat?')
tip = input('How much more, as a percentage, would you like to give as a tip?')

tip = tip/100

print tip

vat = 1.2

cash_vat = cash * vat

can = (cash_vat + ((tip/100) * cash_vat))

can = cash_vat + tip * cash_vat

print """
Thank you for your co-operation.
The price excluding the tip is %r,
and the total price is %d.
"""  % (cash_vat, can)

当上述代码运行时，终端发出：

Welcome to Cash Calculator!
How much was the original price of the services or goods you paid for, excluding vat?100
How much more, as a percentage, would you like to give as a tip?10
0

Thank you for your co-operation.
The price excluding the tip is 120.0,
and the total price is 120.

有什么问题吗？它一直认为小费是0。我完全是个初学者。你知道吗

Answer 1

In Python 2除法运算符/执行整数除法，如果分子和分母都是ints（在本例中是这样，因为您使用了input()）。所以这次行动：

# if tip = 10
tip = 10/100

将返回0，因为两个值的类型都是int。你知道吗

---

由于需要浮点除法，因此可以从^{}模块导入division运算符：

from __future__ import division

tip = 10 / 100 # returns 0.1

或者，在实际除法之前，将类型int的tip强制转换为float：

tip = float(10) / 100 # returns 0.1