while循环

例（1）
count_1 = True
while count_1:
    print('1')
    print('2')
    count_1 = False
print('3')

例（2）
count_1 = True
while count_1:
    print('1')
    print('2')
    count_1 = False
print('3')

例（3）
count_1 = 1
count_2 = True
while count_2:
    print(count_1)
    if count_1 == 100:
        count_2 = False
    count_1 +=1
print('end.....')


例（4）
count_1 = 1
while count_1:
    print(count_1)
    if count_1 == 100:
        break #跳出当前循环
    count_1 +=1
print('end.....')

例（5）
while True:
    print('123')
    continue#结束本次循环跳到下一次循环
    pritn('456')
print('end.....')

例（6）
count_1 = 0
while True:
    if count_1 == 6 or count_1 == 3:
        count_1 += 1
        continue
    print(count_1)
    count_1 += 1
    if count_1 == 10:
        break
print('end.....')

　　

例（7）
count_1 = 1
while count_1 <= 10:
    if count_1 != 3:
        print(count_1)
    count_1 += 1

作业（1）
输出1-100所有的奇数：

start = 1
while start <= 100:
     
    s = start%2
    if s ==  0:
        start += 1
        continue
    print(start)
    start += 1

输出1-100所有的偶数    

start = 1
while start <= 100:
　　s = start%2
　　if s !=  0:
　　　　start += 1
　　　　continue
　　print(start)
　　start += 1

用户名登录3次重试

s = 1
j = 2
while s <= 3:
    name = input('输入用户名：')
    mima = input('输入密码：')
    if name == 'N' and mima == '123':
        print('欢迎登录')
        break
    else:
        print('您还有%s次机会'%j)
        j -= 1
        s += 1
        continue

　　

　

从1加到100：
h = 0
j = 1
while  j <= 100:
    h = h + j
    if j == 100:
        print(h)

    j += 1

　　

　

求1-2+3-4...99的所有数的和
sum = 0
start = 1
while start < 100:
    temp = start % 2
    if temp == 1:
        sum = sum + start
    else:
        sum = sum - start
    start += 1
    print(sum)