Day3_BranchStructure

"""
登陆验证
Author:黄骏捷
Date:2019-09-28
"""
username = input('请输入用户名：')
password = input('请输入口令：')
if username == 'admin' and password == 'admin':
    print('登陆成功')
else:
    print('登陆失败')

print('------------------------------')
"""
分段函数求值

        3x - 5  (x > 1)
f(x) =  x + 2   (-1 <= x <= 1)
        5x + 3  (x < -1)

连续保存相同缩进的代码属同一个代码块
"""
x = float(input('x = '))
if x > 1:
    y = 3 * x - 5
elif x >= -1:
    y = x + 2
else:
    y = 5 * x + 3
print('f(%.2f) = %.2f' % (x, y))
print('------------------------------')
"""
一样的效果
x = float(input('x = '))
if x > 1:
    y = 3 * x - 5
else:
    if x >= -1:
        y = x + 2
    else:
        y = 5 * x + 3
print('f(%.2f) = %.2f' % (x, y))
"""