Python数据结构03分支结构

1.

# 单分支结构#1
# 输入两个整数存放于变量a和b中&＃xff0c;并使得a中存放的数据小于b中存放的数据
a &＃61; int(input(&＃39;Please input 1st integer: &＃39;))
b &＃61; int(input(&＃39;Please input 2nd integer: &＃39;))
print(&＃39;Before processing&＃xff1a; &＃39;)
print(&＃39;a&＃61;%d,b&＃61;%d&＃39;%(a,b))
if a>b:t&＃61;aa&＃61;bb&＃61;t
print(&＃39;After processing: &＃39;)
print(&＃39;a&＃61;%d,b&＃61;%d&＃39;%(a,b))

C:\Users\Amber\AppData\Local\Programs\Python\Python36\python.exe C:/Users/Amber/Desktop/单分支结构——001.py
Please input 1st integer: 3
Please input 2nd integer: 2
Before processing&＃xff1a;
a&＃61;3,b&＃61;2
After processing:
a&＃61;2,b&＃61;3

Process finished with exit code 0

2. 双分支结构

# 双分支结构#1
# 比较两个数的大小&＃xff0c;输入两个整数&＃xff0c;输出较大的数
a &＃61; float(input(&＃39;Please input 1st number: &＃39;))
b &＃61; float(input(&＃39;Please input 2nd number: &＃39;))
if a>b:print(a)
else:print(b)

C:\Users\Amber\AppData\Local\Programs\Python\Python36\python.exe C:/Users/Amber/Desktop/双分支结构#1.py
Please input 1st integer: 3.6
Please input 2nd integer: 7.3
7.3

# 双分支结构#2
# 输入三条边的值&＃xff0c;看是否组成三角形
a &＃61; float(input(&＃39;Please input 1st number: &＃39;))
b &＃61; float(input(&＃39;Please input 2nd number: &＃39;))
c &＃61; float(input(&＃39;Please input 3rd number: &＃39;))
if a&＃43;b>c and b&＃43;c>a and a&＃43;c>b:print("可以组成三角形")
else:print("不可组成三角形")

C:\Users\Amber\AppData\Local\Programs\Python\Python36\python.exe C:/Users/Amber/Desktop/双分支结构#2.py
Please input 1st number: 2
Please input 2nd number: 3
Please input 3rd number: 4
可以组成三角形

# 双分支结构#3
# 划船问题&＃xff0c;一个教师带着x个学生去划船&＃xff0c;每条船最多装4人&＃xff0c;问需要几条船
a &＃61; int(input(&＃39;Please input 学生数目: &＃39;))
total &＃61; a&＃43;1 #总人数将老师也算在内
if total % 4 &＃61;&＃61; 0:n &＃61; total // 4
else:n &＃61; total // 4 &＃43; 1
print("Total required %d boats" %(n))

Connected to pydev debugger (build 181.2784.25)
Please input 学生数目: 5
Total required 2 boats

3. 多分支结构

# 多分支结构#1
# 计算分段函数的值。当x大于1时&＃xff0c;y&＃61;x&＃xff1b;当x小于-1时&＃xff0c;y&＃61;-x&＃xff1b;当x介于-1与1之间时&＃xff0c;y&＃61;1
x &＃61; float(input(&＃39;Please input a number: &＃39;))
if x > 1:y&＃61;x
elif x <-1:y&＃61;-x
else:y&＃61;1
print(y)

# 多分支结构#2
# 某校学生成绩采用百分制mark&＃xff0c;将其该为五级制度
x &＃61; float(input(&＃39;Please input a number: &＃39;))
if x >100:print(&＃39;Error, Please input correct number:&＃39;)
elif x >&＃61; 90:print("A")
elif x >&＃61; 80:print (&＃39;B&＃39;)
elif x >&＃61; 70:print (&＃39;B-&＃39;)
elif x >&＃61; 60:print(&＃39;C&＃39;)
else:print(&＃39;D&＃39;)


# 多分支结构#3
# 已知坐标点&＃xff08;x,y&＃xff09;&＃xff0c;判断所在象限
x &＃61; float(input(&＃39;Please input x: &＃39;))
y &＃61; float(input(&＃39;Please input y: &＃39;))
if x&＃61;&＃61;0 and y&＃61;&＃61;0:print(&＃39;点(%d,%d)在原点:&＃39; %(x,y))
elif x&＃61;&＃61;0 and y!&＃61;0:print(&＃39;点(%d,%d)y-axis:&＃39;%(x,y))
elif x!&＃61;0 and y&＃61;&＃61;0:print(&＃39;点(%d,%d)x-axis:&＃39;%(x,y))
elif x >0 and y>0:print(&＃39;点(%d,%d)第一象限:&＃39;%(x,y))
elif x>0 and y<0:print(&＃39;点(%d,%d)第4象限:&＃39; %(x,y))
elif x <0 and y <0:print(&＃39;点(%d,%d)第3象限:&＃39; %(x,y))
elif x<0 and y>0:print(&＃39;点(%d,%d)第2象限:&＃39; %(x,y))
#else:# print(&＃39;点(%d,%d)坐标轴上:&＃39; %(x,y))

4. 嵌套if语句与逻辑运算

# 判断一年是否为闰年&＃xff0c;闰年条件为&＃xff1a;年份能被4整除但不能被100整除&＃xff0c;或者能被400整除
year &＃61; int(input(&＃39;Please input a year&＃39;))
if year%4 &＃61;&＃61;0 and year % 100 !&＃61;0:print("%d year in run nian"%(year))
elif year%400 &＃61;&＃61;0:print("%d year in run nian" %(year))
else:print("%d year is not run nian" %(year))

# 判断一年是否为闰年&＃xff0c;闰年条件为&＃xff1a;年份能被4整除但不能被100整除&＃xff0c;或者能被400整除
# 使用逻辑判断
year &＃61; int(input(&＃39;Please input a year&＃39;))
if (year%4 &＃61;&＃61;0 and year % 100 !&＃61;0) or (year % 400 &＃61;&＃61; 0):print("%d year in run nian"%(year))
else:print("%d year is not run nian" %(year))

等效形式&＃xff1a;

if (year%4 &＃61;&＃61;0 and year % 100 !&＃61;0) or (year % 400 &＃61;&＃61; 0):

if (year%4 &＃61;&＃61;0 and year % 100) or (year % 400 &＃61;&＃61; 0):

if ((not(year%4) and year % 100) or year % 400 &＃61;&＃61; 0):

5. 编写程序

#输出三个数中最大的那个数
a &＃61; float(input("Please input 1st number"))
b &＃61; float(input("Please input 2nd number"))
c &＃61; float(input("Please input 3rd number"))
if (a >&＃61; b) and (a >&＃61; c):max &＃61; aprint(&＃39;max number is %s&＃39;%(max))
elif (b >&＃61; a) and (b >&＃61; c):max &＃61; bprint(&＃39;max number is %s&＃39;%(max))
else:max &＃61; cprint(&＃39;max number is %s&＃39; % (max))

#输出三个数中最大的那个数/改进方法2
a &＃61; float(input("Please input 1st number"))
b &＃61; float(input("Please input 2nd number"))
c &＃61; float(input("Please input 3rd number"))
max &＃61; a
if (max if (max print(&＃39;max number is %s&＃39;%(max))