Add Lesson 1 Task 2

Lesson_1/task2.py

@@ -0,0 +1,54 @@
+# Lesson 1 Task 2: calculator
+# Author: Stanislav Mykhailenko
+# License: Unlicense
+
+# Return codes:
+# 0 - OK
+# 1 - Invalid numbers entered
+# 2 - Division by zero
+# 3 - Invalid first operation entered
+# 4 - Square root of a negative number calculation
+
+import sys, math
+
+try:
+	numberA = float(input("Enter number A: "))
+	numberB = float(input("Enter number B: "))
+except ValueError:
+	print("Invalid numbers entered.")
+	sys.exit(1)
+
+operation = input("Enter operation (+, − or -, × or *, ÷ or /): ")
+
+# The other part of the task is not clearly defined. It asks to implement square root of a number, or its square, but it can only be done with one number. Assuming it is the result of the first operation and saving it…
+result: float
+
+if operation == "+":
+	result = numberA + numberB
+elif operation == "-" or operation == "−": # ASCII hyphen-minus or Unicode minus
+	result = numberA - numberB
+elif operation == "*" or operation == "×": # ASCII asterisk or Unicode multiplication sign
+	result = numberA * numberB
+elif operation == "/" or operation == "÷": # ASCII slash or Unicode division sign
+	if numberB == 0:
+		print("Division by zero.")
+		sys.exit(2)
+	else:
+		result = numberA / numberB
+else:
+	print("Invalid operation.")
+	sys.exit(3)
+
+print("Result: " + str(result))
+
+# …and asking to do sqrt or square with it.
+secondOperation = input("Do anything else with the result (√ or sqrt, ² or square, any other input will be ignored)? ")
+
+if secondOperation == "√" or secondOperation == "sqrt": # Unicode radical symbol
+	if result < 0:
+		print("Can't get a square root of a negative number.")
+		sys.exit(4)
+	else:
+		print(math.sqrt(result))
+elif secondOperation == "²" or secondOperation == "square": # Unicode superscript 2
+	print(math.pow(result, 2))