📘 Week 2：控制流程

重點：if-else、for、while
練習：畫流程圖，預測執行結果

Day 8：if 判斷

score = 75
if score >= 60:
    print("及格")
else:
    print("不及格")

temperature = 30
if temperature > 35:
    print("太熱了")
elif temperature < 15:
    print("太冷了")
else:
    print("天氣剛好")

age = 18
if age >= 18:
    print("成年")
else:
    print("未成年")

password = "abc123"
if password == "abc123":
    print("登入成功")
else:
    print("密碼錯誤")

Day 9：for 迴圈

for i in range(3):
    print("第", i + 1, "次問候")

for char in "Python":
    print(char)

fruits = ["蘋果", "香蕉", "芒果"]
for fruit in fruits:
    print("我喜歡", fruit)

for num in range(1, 6):
    print(num ** 2)

Day 10：while 迴圈

count = 0
while count < 3:
    print("倒數中:", 3 - count)
    count += 1

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

password = ""
while password != "1234":
    password = input("請輸入密碼: ")
print("密碼正確")

n = 10
while n > 0:
    print(n)
    n -= 2

Day 11：巢狀結構

for i in range(2):
    for j in range(3):
        print(f"i={i}, j={j}")

score = 85
if score >= 60:
    print("及格")
    if score >= 90:
        print("成績優異")

for x in range(1, 4):
    for y in range(1, 4):
        print(x * y, end=" ")
    print()

for i in range(1, 6):
    if i % 2 == 0:
        print(i, "是偶數")
    else:
        print(i, "是奇數")

Day 12：break 與 continue

for i in range(5):
    if i == 3:
        break
    print(i)

for i in range(5):
    if i == 2:
        continue
    print(i)

i = 0
while i < 5:
    if i == 4:
        break
    print(i)
    i += 1

for char in "Python":
    if char == "h":
        continue
    print(char)

Day 13：條件邏輯練習

x = 10
y = 20
if x < y and y < 30:
    print("條件成立")

flag = True
if not flag:
    print("旗標為 False")
else:
    print("旗標為 True")

score = 88
if score >= 90 or score == 88:
    print("成績不錯")

temperature = 22
comfortable = 18 <= temperature <= 28
print("舒適天氣:", comfortable)

Day 14：綜合練習

for i in range(1, 6):
    if i % 2 == 0:
        print(f"{i} 是偶數")
    else:
        print(f"{i} 是奇數")

score = int(input("請輸入分數: "))
if score >= 90:
    print("優等")
elif score >= 75:
    print("甲等")
elif score >= 60:
    print("乙等")
else:
    print("丙等")

i = 1
while i <= 5:
    print("第", i, "次執行")
    i += 1

for x in range(1, 4):
    for y in range(1, 4):
        print(f"{x} × {y} = {x * y}")