一、单分支
if user_name == username and user_password == password:
print("welcome",username)
else:
print("login failed!")
二、双分支
if sex == "girl":
if age < 28:
print("I Love You",user_name)
else:
print("I don't Love You",user_name)
else:
print("Bye...")
二、多分支
if user_guess == age :
print("True")
elif user_guess < age :
print("try bigger")
else:
print("try smaller")
if score > 100:
print("socre don't > 100")
elif score >= 90:
print("You score is A")
elif score >= 80:
print("You score is B")
elif score >= 60:
print("You score is C")
elif score >= 40:
print("You score is D")
elif score >= 0:
print("You score is E")
else:
print("score not < 0")
