分支与循环（2）

1.while循环

#语法:while 条件块：（如果条件永远为真就会死循环）
     #    语句块：
i=1
sum=0
while i<=10:
    sum += i
    i += 1
print(sum)
#
while True:
   anwer=input("输入数字")
   if anwer=="9":
       break
#break跳出整个循环体，continue跳出当前循环，进入下一个循环
i=10
while i < 20:
    i += 1
    if i%2==0:
        continue
    else:
        print(i)
j=0
#
while j<5:
    if j<5:
         print(j)
    j+=1
else:
    print(6)

2.for循环

#for循环
#for 变量 in 可迭代对象：
#   语句块：
for each in "fince":
    print(each)
#while写法(len()获取对象长度)
k=0
while k <len("fince"):
    print("fince"[k])
    k +=1
#1-100和(range生成数字数列 range(stop),range(start,stop),range(start,stop.step))
sun=0
for i in range(1,101):
    sun += i
print(sun)
for j in range(1,10,2):
    print(j)
#素数不能被二整除的数
for n in range(2,10):
    for x in range(2,n):
        if n % x == 0:
            print(n,"=",x,"*",n // x)
            break
    else:
        print(n,"是素数")

九九乘法表

for i in range(1,10):
    for j in range(1,i+1):
        if j<=10:
            print(j, "*", i, "=", i * j, end="	 ")
        else:
            print()
    print()

i=1
while i<10:
    j=1
    while j<=i:
        print(j,"*",i,"=",j*i,end='	')
        j+=1
    print()
    i+=1