jess.py

def decimal2binary(n):
    # check if larger than 255 as per requirements
    if n > 255:
        return "Int too large"
    
    # this is the string we're returning
    binStr = ""

    # this will loop forever if n never gets to or below 0
    while n > 0:
        # check modulo of n
        if n%2 == 0:
            binStr = "0" + binStr
        else:
            binStr = "1" + binStr

        # set n for next iteration, this is our exit condition
        n = n/2

    # return the bin string we built
    return binStr
  
# lets test it out
x = input("What int do you want to convert? ")
output = decimal2binary(x)
print( output )