流程控制

if 条件1:
    ...
elif 条件2:
    ...
else:
    ...

score = 85
if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
elif score >= 70:
    grade = "C"
elif score >= 60:
    grade = "D"
else:
    grade = "F"
print(f"分数 {score} -> 等级 {grade}")

status = "成年人" if age >= 18 else "未成年"

age = 16
status = "成年" if age >= 18 else "未成年"
print(f"{age}岁 -> {status}")
 
n = 7
parity = "偶数" if n % 2 == 0 else "奇数"
print(f"{n} 是{parity}")

# 遍历列表
fruits = ["苹果", "香蕉", "橙子"]
for f in fruits:
    print(f"我喜欢{f}")
 
# range 区间
for i in range(5):           # 0,1,2,3,4
    print(i, end=" ")
print()
 
for i in range(1, 10, 2):    # 1,3,5,7,9
    print(i, end=" ")
print()

i = 0
while i < 5:
    print(i)
    i += 1

# 1+2+...+100
s = 0
i = 1
while i <= 100:
    s += i
    i += 1
print("1 到 100 之和 =", s)

# 找第一个能被 7 整除的数
for n in range(1, 100):
    if n % 7 == 0:
        print("找到：", n)
        break
 
# 跳过偶数
for n in range(1, 11):
    if n % 2 == 0:
        continue
    print(n, end=" ")
print()

for i in range(1, 10):
    for j in range(1, i + 1):
        print(f"{j}*{i}={i*j}", end="\\t")
    print()

# 任务：判断用户输入的数字 n 是否为素数，输出 "是素数" 或 "不是素数"
# 提示：从 2 遍历到 sqrt(n)，如果有能整除的就不是素数
# 期望：输入 17 -> 是素数；输入 18 -> 不是素数
 
import math
n = int(input("请输入一个正整数："))
# 补全代码