python之面向对象

向右看齐 2022-05-21 10:43 135阅读 0赞

![70][]

小栗子1：寻找GPA最高的学生

![70 1][]

#coding=gbk
    class Student:
        def __init__(self, name, hours, qpoints):
            self.name = name
            self.hours = float(hours)
            self.qpoints = float(qpoints)
         
        def getName(self):
            return self.name
         
        def getHours(self):
            return self.hours
         
        def getQPoints(self):
            return self.qpoints
         
        def gpa(self):
            return self.qpoints/self.hours
         
    def makeStudent(infoStr):
        name, hours, qpoints = infoStr.split("\t")
        return Student(name, hours, qpoints)
         
    def main():
        # 打开输入文件
        filename = input("Enter name the grade file: ")
        infile = open(filename, 'r')
        # 设置文件中第一个学生的记录为best
        best = makeStudent(infile.readline())
     
        # 处理文件剩余行数据
        for line in infile:
            # 将每一行数据转换为一个记录
            s = makeStudent(line)
            # 如果该学生是目前GPA最高的，则记录下来
            if s.gpa() > best.gpa():
                best = s
        infile.close()
     
        # 打印GPA成绩最高的学生信息
        print("The best student is:", best.getName())
        print("hours:", best.getHours())
        print("GPA:", best.gpa())
     
    
    main()

小栗子2：铅球轨迹计算

![70 2][]

Projectile.py

from math import sin,cos,radians
    
    class Projectile:
        def __init__(self,angle,velocity,height):
            #根据给定的发射角度、初始速度和位置创建一个投射体对象
            self.xpos=0.0
            self.ypos=height
            theta = radians(angle)
            self.xvel = velocity * cos(theta)
            self.yvel = velocity * sin(theta)
            
        def update(self,time):
            #更新投射体的状态
            self.xpos = self.xpos + time * self.xvel
            yvel1 = self.yvel - 9.8 * time
            self.ypos = self.ypos + time * (self.yvel + yvel1) / 2.0
            self.yvel = yvel1
        
        def getY(self):
            return self.ypos
        
        def getX(self):
            return self.xpos

shot2.py

注意：这个import得改下才能运行，这两个文件是放在一起的。（tt是包名）

from tt.Projectile import Projectile
    
    def getInputs():
        a = eval(input("Enter the launch angle (in degrees):"))
        h = eval(input("Enter the initial velocity (in meters/sec):"))
        v = eval(input("Enter the initial height (in meters):"))
        t = eval(input("Enter the time interval:"))
        return a,v,h,t
    
    def main():
        angle,vel,h0,time = getInputs()
        shot = Projectile(angle,vel,h0)
        while shot.getY()>=0:
            shot.update(time)
        print("\nDistance traveled:{0:0.1f}meters.".format(shot.getX()))
        
    main()

[70]: /images/20220521/464103217d3b4a94a6bbcff6fafa00e8.png
[70 1]: /images/20220521/b69c27b519a64ae5bf52e61a3e42e3e4.png
[70 2]: /images/20220521/f3f349c6194d40a580aecf0e7a87f0cb.png