# 使用 for 循环遍历列表
a = [1, 2, 3, 4]

# n = len(a)
# for i in range(0, n):
#     print(a[i])

# for num in a:
#     print(num)

# 使用 while 循环遍历列表
a = [1, 2, 3, 4]
pos = 0
n = len(a)
while pos < n:
    print(a[pos])
    pos += 1