Question

For this portion of the lab, you will reuse the Python program you wrote before.
That means you will open the lab you wrote in the previous assignment and change it. You should NOT start from scratch. Also, all the requirements/prohibitions from the previous lab MUST also be included /omitted from this lab.   
Redesign the solution so that some portions of the code are repeated. In lab 4 you validated input to ensure that the user entered inputs within certain values. If the user entered an invalid value, the program terminated. Now you will add a loop such that the user gets three chances to enter a valid value. If the user enters an invalid value more than three times in a row, the program should issue an error message and terminate.

The program I wrote before is shown below.

How can I apply the new requirements to reuse this program?

#Get a value from user.
Miles = float(input('How many miles would you like to convert into kilometers: '))

#Condition
if Miles >= 0:

#Convert miles to kilomters
Kilometers = Miles * 1.6

#Display result
print(Miles,"miles is equal to", Kilometers,"kilometers.")

#Get a value from user.
Gallons = float(input('How many gallons would you like to convert into liters: '))

#Condition
if Gallons >= 0:

#Convert gallons to liters
Liters = Gallons * 3.9

#Display result
print(Gallons,"gallons is equal to", Liters,"liters.")

#Get a value from user.
Pounds = float(input('How many pounds would you like to convert into kilograms: '))

#Condition
if Pounds >= 0:

#Convert pounds to kilograms
Kilograms = Pounds * 0.45

   #Display result

   print(Pounds,"pounds is equal to", Kilograms,"kilograms.")

#Get a value from user.
Inches = float(input('How many inches would you like to convert into centimeters: '))

#Condition
if Inches > 0:
  
#Convert inches to centimeters
Centimeters = Inches * 2.54

#Display result
print(Inches,"inches is equal to",Centimeters,"centimeters.")

#Get a value from user.
Fahrenheit = float(input('How many fahrenheit would you like to convert into celsius: '))

#Condition   
if Fahrenheit < 1000:

#Convert fahrenheits to celsius
Celsius =(Fahrenheit - 32) * 5/9

#Display result
print(Fahrenheit,"fahrenheits is equal to",Celsius,"celsius.")

else:
#Display error message
print('Invalid value!')

else:
#Display error message
print('Invalid value!')

else:
#Display error message

else:
#Display error message
print('Invalid value!')

else:

#Display error message
print('Invalid value!')

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

Note: Please maintain proper code spacing (indentation), just copy the code part and paste it in your compiler/IDE directly, no modifications required.

#code

# Get a value from user.
Miles = float(input('How many miles would you like to convert into kilometers: '))
#attempts remaining to get a valid input
attempts_remaining=3
#looping if input value is less than 0
while Miles<0:
    #displaying error message and how many attempts are left
    print('Invalid input! You have '+str(attempts_remaining)+' chance(s) to enter a valid input')
    #reading value again
    Miles=float(input('How many miles would you like to convert into kilometers: '))
    #if value is valid, exiting loop
    if Miles>=0:
        break
    #otherwise, decrementing attempts_remaining
    attempts_remaining-=1
    #if no more attempts remaining, displaying error and exiting
    if attempts_remaining==0:
        print("You entered wrong input many times. Program is terminated")
        exit(0) #exiting program

#if valid input is entered, converting miles to kilomters
Kilometers = Miles * 1.6

# Display result
print(Miles, "miles is equal to", Kilometers, "kilometers.")


# Get a value from user.
Gallons = float(input('\nHow many gallons would you like to convert into liters: '))

#attempts remaining to get a valid input
attempts_remaining=3
#looping if input value is less than 0
while Gallons<0:
    #displaying error message and how many attempts are left
    print('Invalid input! You have '+str(attempts_remaining)+' chance(s) to enter a valid input')
    #reading value again
    Gallons=float(input('How many gallons would you like to convert into liters: '))
    #if value is valid, exiting loop
    if Gallons>=0:
        break
    #otherwise, decrementing attempts_remaining
    attempts_remaining-=1
    #if no more attempts remaining, displaying error and exiting
    if attempts_remaining==0:
        print("You entered wrong input many times. Program is terminated")
        exit(0) #exiting program

# Convert gallons to liters
Liters = Gallons * 3.9
# Display result
print(Gallons, "gallons is equal to", Liters, "liters.")


# Get a value from user.
Pounds = float(input('\nHow many pounds would you like to convert into kilograms: '))

#attempts remaining to get a valid input
attempts_remaining=3
#looping if input value is less than 0
while Pounds<0:
    #displaying error message and how many attempts are left
    print('Invalid input! You have '+str(attempts_remaining)+' chance(s) to enter a valid input')
    #reading value again
    Pounds=float(input('How many pounds would you like to convert into kilograms: '))
    #if value is valid, exiting loop
    if Pounds>=0:
        break
    #otherwise, decrementing attempts_remaining
    attempts_remaining-=1
    #if no more attempts remaining, displaying error and exiting
    if attempts_remaining==0:
        print("You entered wrong input many times. Program is terminated")
        exit(0) #exiting program
# Convert pounds to kilograms
Kilograms = Pounds * 0.45

# Display result

print(Pounds, "pounds is equal to", Kilograms, "kilograms.")

# Get a value from user.
Inches = float(input('\nHow many inches would you like to convert into centimeters: '))
#attempts remaining to get a valid input
attempts_remaining=3
#looping if input value is less than 0
while Inches<0:
    #displaying error message and how many attempts are left
    print('Invalid input! You have '+str(attempts_remaining)+' chance(s) to enter a valid input')
    #reading value again
    Inches=float(input('How many inches would you like to convert into centimeters: '))
    #if value is valid, exiting loop
    if Inches>=0:
        break
    #otherwise, decrementing attempts_remaining
    attempts_remaining-=1
    #if no more attempts remaining, displaying error and exiting
    if attempts_remaining==0:
        print("You entered wrong input many times. Program is terminated")
        exit(0) #exiting program

# Convert inches to centimeters
Centimeters = Inches * 2.54

# Display result
print(Inches, "inches is equal to", Centimeters, "centimeters.")

# Get a value from user.
Fahrenheit = float(input('\nHow many fahrenheit would you like to convert into celsius: '))

#attempts remaining to get a valid input
attempts_remaining=3
#looping if input value is greater than or equal to 1000
while Fahrenheit>=1000:
    #displaying error message and how many attempts are left
    print('Invalid input! You have '+str(attempts_remaining)+' chance(s) to enter a valid input')
    #reading value again
    Fahrenheit=float(input('How many fahrenheit would you like to convert into celsius: '))
    #if value is valid, exiting loop
    if Fahrenheit<1000:
        break
    #otherwise, decrementing attempts_remaining
    attempts_remaining-=1
    #if no more attempts remaining, displaying error and exiting
    if attempts_remaining==0:
        print("You entered wrong input many times. Program is terminated")
        exit(0) #exiting program

# Convert fahrenheits to celsius
Celsius = (Fahrenheit - 32) * 5 / 9

# Display result
print(Fahrenheit, "fahrenheits is equal to", Celsius, "celsius.")

#output

How many miles would you like to convert into kilometers: -2

Invalid input! You have 3 chance(s) to enter a valid input

How many miles would you like to convert into kilometers: -4

Invalid input! You have 2 chance(s) to enter a valid input

How many miles would you like to convert into kilometers: -2673

Invalid input! You have 1 chance(s) to enter a valid input

How many miles would you like to convert into kilometers: 1000

1000.0 miles is equal to 1600.0 kilometers.

How many gallons would you like to convert into liters: -2

Invalid input! You have 3 chance(s) to enter a valid input

How many gallons would you like to convert into liters: 20

20.0 gallons is equal to 78.0 liters.

How many pounds would you like to convert into kilograms: -1

Invalid input! You have 3 chance(s) to enter a valid input

How many pounds would you like to convert into kilograms: -2

Invalid input! You have 2 chance(s) to enter a valid input

How many pounds would you like to convert into kilograms: -23

Invalid input! You have 1 chance(s) to enter a valid input

How many pounds would you like to convert into kilograms: -134

You entered wrong input many times. Program is terminated