Add --output flag to write to file

fibonacci.py

@@ -1,6 +1,9 @@
 #!/usr/bin/env python3
 """Fibonacci sequence calculator with colored output."""
 
+import argparse
+import sys
+
 # ANSI color codes
 GREEN = "\033[32m"
 CYAN = "\033[36m"
@@ -30,18 +33,26 @@ def fibonacci(n: int) -> int:
     return b
 
 
-if __name__ == "__main__":
-    import sys
-    
-    if len(sys.argv) != 2:
-        print(f"Usage: {sys.argv[0]} <n>")
-        sys.exit(1)
+def main():
+    parser = argparse.ArgumentParser(description="Fibonacci sequence calculator")
+    parser.add_argument("n", type=int, help="The position n in the Fibonacci sequence")
+    parser.add_argument("--output", "-o", help="Write output to a file instead of stdout")
+    args = parser.parse_args()
 
     try:
-        n = int(sys.argv[1])
-    except ValueError:
-        print(f"{RED}Error: '{sys.argv[1]}' is not a valid integer{RESET}")
+        result = fibonacci(args.n)
+    except ValueError as e:
+        print(f"{RED}Error: {e}{RESET}")
         sys.exit(1)
 
-    result = fibonacci(n)
-    print(f"{CYAN}fibonacci({n}){RESET} {GREEN}={RESET} {GREEN}{result}{RESET}")
+    output_line = f"{CYAN}fibonacci({args.n}){RESET} {GREEN}={RESET} {GREEN}{result}{RESET}"
+
+    if args.output:
+        with open(args.output, "w") as f:
+            f.write(output_line + "\n")
+    else:
+        print(output_line)
+
+
+if __name__ == "__main__":
+    main()