Simple-Calculator.md

12.1 Simple Calculator

The task

Create a simple calculator. That will be able to take user input of two numbers and the operation the user wants to perform.

Solution strategy

Create a bunch of functions to perform add, subtract, multiply, division or modulo.

Then take two numbers from the user and the operation he/she wants to perform. Either +,-,*,/ or %.

Then call the appropriate function based on the operation.

Think for a few minutes and try it yourself first.

The solution

def add(num1, num2):
 return num1 + num2
 
def subtract(num1, num2):
 return num1 - num2
 
def multiply(num1, num2):
 return num1 * num2
 
def divide(num1, num2):
 return num1 / num2
 
def modulo(num1, num2):
 return num1 % num2
 
# Take input from the user
num1 = int(input("Enter first number: "))
operation = input("What you want to do(+, -, *, /, %):")
num2 = int(input("Enter second number: "))
 
result = 0
if operation == '+':
 result = add(num1,num2)
elif operation == '-':
 result = subtract(num1,num2)
elif operation == '*':
 result = multiply(num1,num2)
elif operation == '/':
 result = divide(num1,num2)
elif operation == '%':
 result = modulo(num1,num2)
else:
 print("Please enter: +, -, *, / or %")
 
print(num1, operation, num2, '=', result)

Try it on Programming Hero

How it works

You saw five functions to add, subtracts, etc. Those are easy.

Then we are taking user inputs. Three inputs. They are easy too.

Then we have if-elif-else. And based on the operation, we call the right method to perform the task.

That’s it.

   

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