python学习第二课——while循环

#while循环基础语句

while 1==1:
   print('OK') #死循环

#如何阻止死循环

count=0
while count<10:
    print('第'+(str)(count)+'次循环') #定义的为int 所以必须用str将其转化为字符串
    count=count+1
print('循环结束')

#continue

continue用于退出当前循环，直接进去下一次循环

while  True:
    print("123")
    continue
    print("456")

#break

break用于中断所有循环

while  True:
    print("123")
    break
    print("456")

#while循环练习题

1、使用while循环输入1 2 3 4 5 6  8 9 10

count = 1
while count<=10 :
    if count == 7:
        pass
    else:
        print(count)
    count=count+1
print("循环结束")

2、求1-100的所有数的和

count = 1
su=0
while count<=100:
    su+=count
    count=count+1
print(su)

3、输出1-100的所有奇数

count = 1
while count <= 100:
    if count % 2!=0:
        print(count)
    count=count+1

4、输出1-100的所有偶数

count = 1
while count <= 100:
    if count % 2==0:
        print(count)
    count=count+1

5、求1-2+3-4+5+...+99的所有数的和（方法1）

#可以将其分解为(1+3+5+...+99)-(2+4+6+...+98)

count = 1
su=0
while count < 100:
    if count % 2!=0:
        su+=count
    count=count+1
print('奇数之和为'+(str)(su))
count1 = 1
su1=0
while count1 < 100:
    if count1 % 2==0:
        su1+=count1
    count1=count1+1
print('偶数之和为'+(str)(su1))
print('(1+3+5+...+99)-(2+4+6+...+98)'+'='+(str)(su-su1))

　方法2：

count = 1
su=0
while count<100:
    temp=count%2
    if temp ==0:
        su=su-count
    else:
        su=su+count
    count=count+1
print(su)