生成100以内的加减法算式,隐含要求结果也是100以内。 (1) 实现BinaryOperation及其子类; (2) 实现Exercise和ExerciseSheet类
时间: 2024-04-30 07:23:46 浏览: 18
1. BinaryOperation及其子类实现
首先,我们需要实现一个BinaryOperation类,它有两个属性num1和num2,代表两个操作数。此外,它还应该有一个抽象方法calculate,用来计算并返回结果。
```python
class BinaryOperation:
def __init__(self, num1, num2):
self.num1 = num1
self.num2 = num2
def calculate(self):
pass
```
然后,我们需要实现加法和减法的子类Addition和Subtraction。这两个子类都需要实现calculate方法,分别返回两个操作数的和和差。
```python
class Addition(BinaryOperation):
def calculate(self):
return self.num1 + self.num2
class Subtraction(BinaryOperation):
def calculate(self):
return self.num1 - self.num2
```
2. Exercise和ExerciseSheet类实现
接下来,我们需要实现Exercise和ExerciseSheet类。Exercise类代表一个算式,包含两个操作数和一个运算符,可以通过generate方法生成一个随机的算式。ExerciseSheet类代表一份练习册,包含多个Exercise,可以通过generate方法生成若干个随机的算式。
```python
import random
class Exercise:
def __init__(self, num1, num2, operator):
self.num1 = num1
self.num2 = num2
self.operator = operator
def __str__(self):
return f"{self.num1} {self.operator} {self.num2} ="
def generate(self, max_num=100):
self.num1 = random.randint(0, max_num)
self.num2 = random.randint(0, max_num)
self.operator = random.choice(["+", "-"])
if self.operator == "-":
self.num1, self.num2 = max(self.num1, self.num2), min(self.num1, self.num2)
return self
class ExerciseSheet:
def __init__(self, num_exercises=10):
self.num_exercises = num_exercises
self.exercises = []
def __str__(self):
return "\n".join([f"{i + 1}. {exercise}" for i, exercise in enumerate(self.exercises)])
def generate(self):
self.exercises = [Exercise(0, 0, "") for _ in range(self.num_exercises)]
for exercise in self.exercises:
exercise.generate()
while exercise.operator == "-" and exercise.num1 < exercise.num2:
exercise.generate()
return self
```
Exercise类的generate方法会随机生成两个操作数和一个运算符,然后返回生成的Exercise对象。注意,如果运算符是减号,我们需要保证被减数大于等于减数。
ExerciseSheet类的generate方法会生成若干个随机的Exercise对象,并返回生成的ExerciseSheet对象。注意,对于每个Exercise对象,我们需要保证被减数大于等于减数。
下面是示例代码:
```python
exercise_sheet = ExerciseSheet(num_exercises=10)
exercise_sheet.generate()
print(exercise_sheet)
```
输出:
```
1. 91 - 53 =
2. 19 - 3 =
3. 67 - 1 =
4. 54 + 13 =
5. 87 - 50 =
6. 17 + 35 =
7. 18 - 7 =
8. 100 - 48 =
9. 88 - 48 =
10. 46 - 26 =
```