4.21

4.21.py

@@ -0,0 +1,35 @@
+s = "Hello"
+print("1. 字符 ASCII 码:")
+for ch in s:
+    print(f"  '{ch}' -> {ord(ch)}")
+
+
+print("\n2. 验证 chr(65):")
+print(f"  chr(65) = '{chr(65)}'")
+
+
+A = [3, 4]
+B = [1, 2]
+
+
+
+def add_vectors(v1, v2):
+    return [v1[0] + v2[0], v1[1] + v2[1]]
+
+
+
+def scalar_multiply(scalar, v):
+    return [scalar * v[0], scalar * v[1]]
+
+
+
+import math
+def vector_length(v):
+    return math.sqrt(v[0]**2 + v[1]**2)
+
+print("\n3. 向量计算:")
+print(f"  A = {A}")
+print(f"  B = {B}")
+print(f"  A + B = {add_vectors(A, B)}")
+print(f"  2 × A = {scalar_multiply(2, A)}")
+print(f"  A 的模 = {vector_length(A)}")