Python 3.5.1 - Give User 3 Invalid Attempts Then Terminate Pgm (simple For Loop)

I need assistance (new student - 2 weeks). I'd like to get the most minimal changes possible to this code that allows a user 3 chances at typing in the incorrect values for each c

Solution 1:

The easiest for you is probably to make a loop for each prompt like in the following pseudo Python code:

# Beginning of prompt
i = 0while i < 3:
    result = float(input(<question>))
    if <isok>:
        print(<result>)
        breakelse:
        print(<error>)
    i += 1# Three failed inputs.if i == 3:
    print('Bye, bye!')
    sys.exit(1)

at each <...> you will have to write something sensible for your program.

UPDATE

A variant with for loop:

# Beginning of prompt
ok = Falsefor i inrange(3):
    result = float(input(<question>))
    if <isok>:
        print(<result>)
        ok = Truebreakelse:
        print(<error>)
# Three failed inputs.ifnot ok:
    print('Bye, bye!')
    sys.exit(1)

Remember ok = False before each for loop.

UPDATE 2

This is the whole program as I see it, where you get 3 chances on each input. I have taken the liberty of adjusting your print statements.

import sys

# Beginning of prompt
ok = Falsefor i inrange(3):
    miles = float(input('Type miles to be converted to km.\n'))
    if miles >= 0:
        milesToKm = miles * 1.6print('{} miles is {:.1f} kilometers.'.format(miles, milesToKm))
        ok = Truebreakelse:
        print('Wrong input, no negatives.')
# Three failed inputs.ifnot ok:
    print('Bye, bye!')
    sys.exit(1)

# Beginning of prompt
ok = Falsefor i inrange(3):
    inch = float(input('Give me inches to convert to cm.\n'))
    if inch >= 0:
        inchesToCm = inch * 2.54print('{} inches is {:.2f} centimeters.'.format(inch, inchesToCm))
        ok = Truebreakelse:
        print('Wrong input, no negatives.')
# Three failed inputs.ifnot ok:
    print('Bye, bye!')
    sys.exit(1)

# Beginning of prompt
ok = Falsefor i inrange(3):
    temp = float(input('Give me a Fahrenheit temp to convert to Celsius.\n'))
    if temp <= 1000:
        celsius = (temp - 32) * (5 / 9)
        print('{} degrees Fahrenheit is {:.1f} Celsius.'.format(temp, celsius))
        ok = Truebreakelse:
        print('Wrong input, too high.')
# Three failed inputs.ifnot ok:
    print('Bye, bye!')
    sys.exit(1)

print('All OK')