Update calculator with python2

calculator with python2

@@ -1,87 +1,162 @@
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-# Program make a simple calculator
-
-# This function adds two numbers
-def add(x, y):
-    return x + y
-
-# This function subtracts two numbers
-def subtract(x, y):
-    return x - y
-
-# This function multiplies two numbers
-def multiply(x, y):
-    return x * y
-
-# This function divides two numbers
-def divide(x, y):
-    return x / y
-
-
-print("Select operation.")
-print("1.Add")
-print("2.Subtract")
-print("3.Multiply")
-print("4.Divide")
-
-while True:
-    # take input from the user
-    choice = input("Enter choice(1/2/3/4): ")
-
-    # check if choice is one of the four options
-    if choice in ('1', '2', '3', '4'):
-        num1 = float(input("Enter first number: "))
-        num2 = float(input("Enter second number: "))
-
-        if choice == '1':
-            print(num1, "+", num2, "=", add(num1, num2))
-
-        elif choice == '2':
-            print(num1, "-", num2, "=", subtract(num1, num2))
-
-        elif choice == '3':
-            print(num1, "*", num2, "=", multiply(num1, num2))
-
-        elif choice == '4':
-            print(num1, "/", num2, "=", divide(num1, num2))
-
-        # check if user wants another calculation
-        # break the while loop if answer is no
-        next_calculation = input("Let's do next calculation? (yes/no): ")
-        if next_calculation == "no":
-          break
-
-    else:
-        print("Invalid Input")
+# Python program to create a simple GUI
+# calculator using Tkinter
+
+# importing everything from tkinter module
+from tkinter import *
+
+# globally declare the expression variable
+expression = ""
+
+
+# Function to update expression variable
+# in the text entry box
+def press(num):
+    # point out the global expression variable
+    global expression
+
+    # concatenation of string
+    expression = expression + str(num)
+
+    # update the expression by using set method
+    equation.set(expression)
+
+
+# Function to evaluate the final expression
+def equalpress():
+    # Try and except statement is used
+    # for handling the errors like zero
+    # division error etc.
+
+    # Put that code inside the try block
+    # which may generate the error
+    try:
+
+        global expression
+
+        # eval function evaluate the expression
+        # and str function convert the result
+        # into string
+        total = str(eval(expression))
+
+        equation.set(total)
+
+        # initialize the expression variable
+        # by empty string
+        expression = ""
+
+    # if error is generate then handle
+    # by the except block
+    except:
+
+        equation.set(" error ")
+        expression = ""
+
+
+# Function to clear the contents
+# of text entry box
+def clear():
+    global expression
+    expression = ""
+    equation.set("")
+
+
+# Driver code
+if __name__ == "__main__":
+    # create a GUI window
+    gui = Tk()
+
+    # set the background colour of GUI window
+    gui.configure(background="light green")
+
+    # set the title of GUI window
+    gui.title("Simple Calculator")
+
+    # set the configuration of GUI window
+    gui.geometry("270x150")
+
+    # StringVar() is the variable class
+    # we create an instance of this class
+    equation = StringVar()
+
+    # create the text entry box for
+    # showing the expression .
+    expression_field = Entry(gui, textvariable=equation)
+
+    # grid method is used for placing
+    # the widgets at respective positions
+    # in table like structure .
+    expression_field.grid(columnspan=4, ipadx=70)
+
+    # create a Buttons and place at a particular
+    # location inside the root window .
+    # when user press the button, the command or
+    # function affiliated to that button is executed .
+    button1 = Button(gui, text=' 1 ', fg='black', bg='red',
+                    command=lambda: press(1), height=1, width=7)
+    button1.grid(row=2, column=0)
+
+    button2 = Button(gui, text=' 2 ', fg='black', bg='red',
+                    command=lambda: press(2), height=1, width=7)
+    button2.grid(row=2, column=1)
+
+    button3 = Button(gui, text=' 3 ', fg='black', bg='red',
+                    command=lambda: press(3), height=1, width=7)
+    button3.grid(row=2, column=2)
+
+    button4 = Button(gui, text=' 4 ', fg='black', bg='red',
+                    command=lambda: press(4), height=1, width=7)
+    button4.grid(row=3, column=0)
+
+    button5 = Button(gui, text=' 5 ', fg='black', bg='red',
+                    command=lambda: press(5), height=1, width=7)
+    button5.grid(row=3, column=1)
+
+    button6 = Button(gui, text=' 6 ', fg='black', bg='red',
+                    command=lambda: press(6), height=1, width=7)
+    button6.grid(row=3, column=2)
+
+    button7 = Button(gui, text=' 7 ', fg='black', bg='red',
+                    command=lambda: press(7), height=1, width=7)
+    button7.grid(row=4, column=0)
+
+    button8 = Button(gui, text=' 8 ', fg='black', bg='red',
+                    command=lambda: press(8), height=1, width=7)
+    button8.grid(row=4, column=1)
+
+    button9 = Button(gui, text=' 9 ', fg='black', bg='red',
+                    command=lambda: press(9), height=1, width=7)
+    button9.grid(row=4, column=2)
+
+    button0 = Button(gui, text=' 0 ', fg='black', bg='red',
+                    command=lambda: press(0), height=1, width=7)
+    button0.grid(row=5, column=0)
+
+    plus = Button(gui, text=' + ', fg='black', bg='red',
+                command=lambda: press("+"), height=1, width=7)
+    plus.grid(row=2, column=3)
+
+    minus = Button(gui, text=' - ', fg='black', bg='red',
+                command=lambda: press("-"), height=1, width=7)
+    minus.grid(row=3, column=3)
+
+    multiply = Button(gui, text=' * ', fg='black', bg='red',
+                    command=lambda: press("*"), height=1, width=7)
+    multiply.grid(row=4, column=3)
+
+    divide = Button(gui, text=' / ', fg='black', bg='red',
+                    command=lambda: press("/"), height=1, width=7)
+    divide.grid(row=5, column=3)
+
+    equal = Button(gui, text=' = ', fg='black', bg='red',
+                command=equalpress, height=1, width=7)
+    equal.grid(row=5, column=2)
+
+    clear = Button(gui, text='Clear', fg='black', bg='red',
+                command=clear, height=1, width=7)
+    clear.grid(row=5, column='1')
+
+    Decimal= Button(gui, text='.', fg='black', bg='red',
+                    command=lambda: press('.'), height=1, width=7)
+    Decimal.grid(row=6, column=0)
+    # start the GUI
+    gui.mainloop()