Question

from math import *
class GeometricObject():
     def __init__(self, color = "green", filled = True):
        self.color = color
        self.filled = filled

    def __str__(self):
        return "color: " + self.__color + \
               " and filled: " + str(self.__filled)


class Triangle(GeometricObject):
    def __init__(self, side1 = 1, side2 = 1, side3 = 1):
        super().__init__()
        self.side1 = float(side1)
        self.side2 = float(side2)
        self.side3 = float(side3)

    def getArea(self):
        return self.area

    def setArea(self, side1, side2, side3):
        s = (side1 + side2 + side3)/2
        area = sqrt(s*(s-side1)*(s-side2)*(s-side3))
        self.area = area

    def getPerimeter(self):
        return self.perimeter

    def setPerimeter(self, side1, side2, side3):
        perimeter = side1 + side2 + side3
        self.perimeter = perimeter

    def __str__(self):
        return "Triangle: " + "side 1 = " + str(self.side1)+ \
               " " + "side 2 = " + str(self.side2) + " " + \
                "side 3 = " + str(self.side3)

def main():
    side1 = eval(input("Enter a value for side 1: "))
    side2 = eval(input("Now enter a value for side 2: "))
    side3 = eval(input("Now enter a value for side 3: "))
    color = input("Enter the color of the triangle: ")
    filled = input("Enter true(filled) or false(not filled) " + \
                   "for the triangle being filled: ")
    go = GeometricObject(color, filled)
    tri = Triangle(side1, side2, side3)
    tri.setArea(side1, side2, side3)
    tri.setPerimeter(side1, side2, side3)

    print("\n\n")
    print("A Triangle: ", tri.__str__(), go.__str__())
    print("The area is: ", tri.getArea())
    print("The perimeter is: ", tri.getPerimeter())

main()

以上是我的代码和我得到的错误我不明白，大部分代码都直接来自书中的示例并进行了调整以适合我的程序。我能做些什么来让我按照我需要的方式工作。这是用于家庭作业，我可以真正使用一些帮助来找出我的代码中的错误。

这不是一个错误但是如何在其他三角形信息之后显示GeometricObject颜色和填充属性。

Enter a value for side 1: 3
Now enter a value for side 2: 4
Now enter a value for side 3: 5
Enter the color of the triangle: blue
Enter 1(filled) or 0(not filled) for the triangle being filled: 1



A Triangle:  Triangle: side 1 = 3.0 side 2 = 4.0 side 3 = 5.0 <__main__.GeometricObject object at 0x000000000312EA20>
The area is:  6.0
The perimeter is:  12

Answer 1

问题是tri.__str__中的实例变量未被正确访问。要访问属于该类实例的变量，您需要在名称前添加self.

函数中的变量名称也不正确：它们应该是__side1，__side2和__side3。

将__str__函数替换为此函数，它应该可以正常工作：

def __str__(self):
    return "Triangle: " + "side 1 = " + str(self.__side1) +\
            "side 2 = " + str(self.__side2) + "side 3 = " + str(self.__side3)

Answer 2

你的问题在于这个功能：

def __str__(self):
  return "Triangle: " + "side 1 = " + str(side1) +\
    "side 2 = " + str(side2) + "side 3 = " + str(side3)

NameError表示它无法识别变量'side1'，因为'side1'从未在该范围内声明。

现在，一个问题：side1，side2和side3从哪里被引用？你怎么能改变它们？

python全局名称未定义 - 作业

2 个答案: