print("===== 题目1 运行结果 =====")
s = "Hello"
print("字符串 'Hello' 每个字符的ASCII码：")
for char in s:
    print(f"字符 '{char}' 的ASCII码为：{ord(char)}")
print("\n验证chr(65)：")
print(f"ASCII码65对应的字符是：{chr(65)}")

print("\n" + "="*50 + "\n")

print("===== 题目3 运行结果 =====")
A = [3, 4]
B = [1, 2]

A_plus_B = [A[0] + B[0], A[1] + B[1]]
print(f"A + B 的结果：{A_plus_B}")

A_times_2 = [2 * A[0], 2 * A[1]]
print(f"2 × A 的结果：{A_times_2}")

import math
A_norm = math.sqrt(A[0]**2 + A[1]**2)
print(f"A 的模（长度）：{A_norm}")

print("\n" + "="*50 + "\n")

print("===== 题目4 运行结果 =====")
A1 = [1, 2, 3]
B1 = [4, 5, 6]

dot_product = sum(a * b for a, b in zip(A1, B1))
print(f"A·B 的点积：{dot_product}")

norm_A1 = math.sqrt(sum(a**2 for a in A1))
norm_B1 = math.sqrt(sum(b**2 for b in B1))
cos_similarity = dot_product / (norm_A1 * norm_B1)
print(f"A 和 B 的余弦相似度：{cos_similarity:.4f}")

A2 = [1, 0]
B2 = [0, 1]
dot_product2 = sum(a * b for a, b in zip(A2, B2))
norm_A2 = math.sqrt(sum(a**2 for a in A2))
norm_B2 = math.sqrt(sum(b**2 for b in B2))
cos_similarity2 = dot_product2 / (norm_A2 * norm_B2)
print(f"\n向量 A={A2} 和 B={B2} 的余弦相似度：{cos_similarity2}")
print("原因：两个向量相互垂直（正交），方向完全不同，因此余弦相似度为0")