Chapter folders renamed

Chapter04/errors/abc.txt

@@ -0,0 +1 @@
+Hello WorldEnd

Chapter04/errors/exception1.py

@@ -0,0 +1,15 @@
+#exception1.py
+try:
+    #print (x)
+    x = 5
+    y = 1
+    z = x /y
+    print('x'+y)
+
+except NameError as e:
+    print(e)
+except ZeroDivisionError:
+    print("Division by 0 is not allowed")
+except Exception as e:
+    print("An error occured")
+    print(e)

Chapter04/errors/exception2.py

@@ -0,0 +1,10 @@
+#exception2.py
+try:
+    f = open("abc.txt", "w")
+except Exception as e:
+    print("Error:" + e)
+else:
+    f.write("Hello World")
+    f.write("End")
+finally:
+    f.close()

Chapter04/errors/exception3.py

@@ -0,0 +1,18 @@
+#exception3.py
+import math
+def sqrt(num):
+
+    if not isinstance(num, (int, float)) :
+        raise TypeError("only numbers are allowed")
+    if num < 0:
+        raise Exception ("Negative number not supported")
+
+    return math.sqrt(num)
+
+if __name__ == "__main__":
+    try:
+        print(sqrt(9))
+        print(sqrt('a'))
+        print (sqrt(-9))
+    except Exception as e:
+        print(e)

Chapter04/errors/exception4.py

@@ -0,0 +1,28 @@
+#exception3.py
+import math
+
+class NumTypeError(TypeError):
+    pass
+
+class NegativeNumError(Exception):
+    def __init__(self):
+        super().__init__("Negative number not supported")
+
+def sqrt(num):
+
+    if not isinstance(num, (int, float)) :
+        raise NumTypeError("only numbers are allowed")
+    if num < 0:
+        raise NegativeNumError
+
+    return math.sqrt(num)
+
+if __name__ == "__main__":
+    try:
+        print(sqrt(9))
+        print(sqrt('a'))
+        print (sqrt(-9))
+    except NumTypeError as e:
+        print(e)
+    except NegativeNumError as e:
+        print(e)