Command line utility

#there are two types of command line arguments are there
#1. positional arguments
    #- we can give value arguments directly in WPS (windows powershell)
    #- cant skip any value argument
    #- expected command in WPS for command line argument program execution ( 4 6 add [note:cant change position])
    
#2. optional arguments
    #- we have to give value arguments in WPS with (--argument_name  argument_value)
    #- we can skip any value argument
    #- expected command in WPS for program execution (--number1 4 --number2 6 --operation add [note:can change position])

import argparse #python built in library
import sys
if __name__=='__main__':
    parser=argparse.ArgumentParser() #parser object
    # 1. positional arguments
    # using add_argument function or attribute adding arguments
    '''parser.add_argument("num1", help="first number")
    parser.add_argument("num2", help="second number")
    parser.add_argument("operation", help="operation")'''

    #'''
    #2. optional arguments
    # using add_argument function or attribute of parser object adding arguments
    #parameters of add_argument function (argument_name, type, default, help)
    parser.add_argument("--num1", type= int, default= 10, help="first number or contact harish")
    parser.add_argument("--num2",type= int,default=5, help="second number or contact harish")
    parser.add_argument("--operation", type=str,default= "add", help="operation or contact harish")
    #'''
    #using parse_args function or attribute of parser object parsing arguments
    args=parser.parse_args()
    #printing output argument values
    print(args.num1)
    print(args.num2)
    print(args.operation)

    #converting arguments value to int because they are by default strings
    n1=int(args.num1)
    n2=int(args.num2)
    result=None
    if (args.operation) == "add":
        result= n1+n2
    elif (args.operation)== "sub":
        result= n1-n2
    elif (args.operation)== "mul":
        result= n1*n2
    elif (args.operation)== "div":
        result= n1/n2
    else:
        print("unsupported operation")

    print("result:", result)
    sys.stdout.write(str(result)) #code to throw the output by sys module