User:RaiseAfloppaFan3925/Program forms

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User-friendly iterative Fibonacci program

This program calculates the given Fibonacci number using the iterative method instead of the classic recursive method. However, it must have a user-friendly interface that loops asking the user forever until an exit is requested. Additionally, if the language's numeric type of choice won't be able to EXACTLY represent the Fibonacci value (for example, with floating-point precision errors in JavaScript and its languages TypeScript, Bussin/Bussin X, Yappacino, and Nonstraightforward, or with integer size limits), it must print Resulting value would be too large. Try again. for any input that would produce an out-of-range Fibonacci number.

Outcomes

Here are the outcomes for all possible user inputs.

Any non-negative number

Example with the 40th Fibonacci number

Input a number: 40
F(40) = 102234155

Any negative number

Example with -39

Input a number: -39
Cannot get a negative Fibonacci number. Try again.

help

Input a number: help
'help' to see this
'exit' to exit

exit

Exits the program.

any non-command, non-numeric inputs

Input a number: 重音テト
Invalid number. Try again.
Input a number: NaN
Invalid number. Try again.
Input a number: --help
Invalid number. Try again.

Examples

🍡Dango

Golfed, works with 0.11.0 interpreter and up (previous 0.10.0 interpreter has an issue in :io-input where the newline (carriage return and newline on Windows) is not removed)

(j)(11)(while)(=)(')(exit)---- fetch 0 fetch 0 (:io-input)(0)---- eat (')(Input a number: )----
(j)(1)---- eat eat eat eat (')('exit' to exit)('c)(10)(')('help' to see this)('c)(10)---- (while)(=)(')(help)----
(j)(1)---- eat eat (')(Invalid number. Try again.)('c)(10)---- (while)(=)()---- fetch 0 (`)
(j)(1)---- eat eat (')(Cannot get a negative Fibonacci number. Try again.)('c)(10)(while)(<)(0)---- fetch 0
(j)(1)---- eat eat (')(Resulting value would be too large. Try again.)('c)(10)(while)(>)(92)---- fetch 0
(j)(10)(0)(while)(=)(0)---- fetch 0
(j)(10)(1)(while)(=)(1)---- fetch 0
(1)(1)(0)---- fetch 0
(j)(9)(while)(<)---- fetch 4 fetch 0 (+)(1)---- fetch 4 fetch 2 fetch 3 fetch 4 (+)---- fetch 2 fetch 2
(j)(1)---- eat ('c)(10)---- eat eat eat ('c)(41)(')( = )---- eat eat (')(F()----

Python

def fib(n):
    if n == 0: return 0
    previous = 0
    current = 1
    for i in range(1, n):
        next = previous + current
        previous = current
        current = next
    return current

while True:
    string = input("Input a number: ")
    if string == 'exit': break
    elif string == 'help':
        print("'help' to see this")
        print("'exit' to exit")
    else:
        try:
            value = int(string)
            if value < 0:
                print('Cannot get a negative Fibonacci number. Try again.')
            else:
                print(f'F({value}) = {fib(value)}')
        except:
            print("Invalid number. Try again.")

Golfed

def f(n):
    a=0;b=1;i=1
    while i<n:c=a+b;a=b;b=c;i+=1
    return b if n>0 else 0
while 1:
    a=input("Input a number: ")    
    match a:
        case'exit':break
        case'help':print("'help' to see this\n'exit' to exit")
        case _:
            try:b=int(a);print('Cannot get a negative Fibonacci number. Try again.'if b<0 else f'F({b}) = {f(b)}')
            except:print("Invalid number. Try again.")