python入门练习题

###1、使用while循环输入 1 2 3 4 5 6 8 9 10

num = 1
while num<=10:
if num ==7:
    num += 1
    continue
print(num)
num += 1

###2、求1-100的所有数的和
num = 1
sum = 0
while num<=100:
sum += num
num += 1
print(sum)

###3、输出 1-100 内的所有奇数
num = 1
while num<=100:
if num%2 ==0:
num += 1
continue
print(num)
num +=1

###4、求1-2+3-4+5 … 99的所有数的和
num = 1
sum = 0
while num<=100:
if num%2 ==0:
sum += num
else:
sum -= num
num +=1
print(sum)

###5.用户登陆（三次机会重试）
count = 0
while True:
usrname = input(“usrname>>>”)
password = input(“password>>>”)
if usrname == “zaoyufeifei” and password ==”123456”:
print(“enter ok”)
break
else:
print(“usrname or password false,please again”)
count +=1
if count==3:
print(“3 times over,you are false”)
break
continue