My solution to Reddit Daily Programmer 331 (Easy)

Reddit Daily Programmer331 (Easy).py

# https://www.reddit.com/r/dailyprogrammer/comments/6ze9z0/20170911_challenge_331_easy_the_adding_calculator/
# Make a calculator that uses addition only to calculate Sum, Difference,
#   Product, Division, and Exponentation

# Python 3 does not have a defined min value for Int and cannot overflow,
#  therefore can't use a clearer method to get a negative one.
# The find function returns -1 if it does not locate the search string.
negOne="a".find("b")


#
#Functions
#

def Invert(op1):
    j=0
    if op1 > 0: #pos to neg
        for i in range(0,op1):
            j=Add(j,negOne)
    elif op1 < 0: #neg to pos
        for i in range(op1,0):
            j+=1
    return(j)

def Add(op1, op2):
    return (op1+op2)

def Absolute(op1):
    if op1>=0: #non-negative
        return op1
    else: #negative, count up from op1 to 0
        j=0
        for i in range(op1,0):
            j+=1
        return(j)

def Sub(op1, op2):
    invFlag=False
    if(op2 > op1):  #swap order to take smaller value from larger, mark to invert
        origOp1=op1
        op1=op2
        op2=origOp1
        invFlag=True
    j=0
    for i in range (op2,op1):
        j+=1
    if invFlag:
        j=Invert(j)
    return(j)

def Mult(op1, op2):
    result = 0
    negative=False #assume positive

    # check for zeros
    if op1==0 or op2==0:
        return 0

    #Check for sign of result, mixed signs mean negative result
    if (op1>0 and op2<0) or (op1<0 and op2>0):
        negative=True
    op1=Absolute(op1) #take absolute value even if not needed - simplifies code
    op2=Absolute(op2)
    for i in range(0,op2):
        result = Add(result,op1)
    if negative==False:
        return(result)
    else:
        return(Invert(result))

def Div(op1, op2): # 9 / 3 = 3
    negative=False #assume positive
    if(op2==0):             #div by zero
        return("Error: Divide by zero")
    if (op1>0 and op2<0) or (op1<0 and op2>0):
        negative=True
    op1=Absolute(op1) #take absolute value even if not needed - simplifies code
    op2=Absolute(op2)
    j=0
    acc=0
    while(acc < op1):
        acc=Add(acc,op2)
        j+=1
    if(acc==op1): #Whole number
        if negative==False:
            return(j)
        else:
            return(Invert(j))
    else:                   #non-integer
        return("Error: Non-Integer")

def Exp(op1, op2):
    #edge cases
    if(op2==0):
        return(1)
    if(op1==0):
        return(0)
    if(op2 < 0):         #negative exponents not allowed (non-integer)
        return("Error: Non-Integer")
    acc=op1
    for i in range(1,op2):
       acc=Mult(acc,op1)
       #print("i={} and acc={}".format(i, acc))
    return(acc)


def ParseInput(inputStr):
    splitVals=inputStr.split()
    return(splitVals[1], int(splitVals[0]), int(splitVals[2]))

def CalculatorAddOnly(inputStr):
    inputList=ParseInput(inputStr)

    if(inputList[0]=="-"):
        outputVal=Sub(inputList[1],inputList[2])
    elif(inputList[0]=="+"):
        outputVal=Add(inputList[1],inputList[2])
    elif(inputList[0]=="*"):
        outputVal=Mult(inputList[1],inputList[2])
    elif(inputList[0]=="/"):
        outputVal=Div(inputList[1],inputList[2])
    elif(inputList[0]=="^"):
        outputVal=Exp(inputList[1],inputList[2])
    else:
        outputVal="Unknown operator"

    print(inputStr + " = {}".format(outputVal))

#
# Main
#

CalculatorAddOnly("12 + 25")
CalculatorAddOnly("-30 + 100")
CalculatorAddOnly("100 - 30")
CalculatorAddOnly("100 - -30")
CalculatorAddOnly("-25 - 29")
CalculatorAddOnly("-41 - -10")
CalculatorAddOnly("9 * 3")
CalculatorAddOnly("9 * -4")
CalculatorAddOnly("-4 * 8")
CalculatorAddOnly("-12 * -9")
CalculatorAddOnly("100 / 2")
CalculatorAddOnly("75 / -3")
CalculatorAddOnly("-75 / 3")
CalculatorAddOnly("7 / 3")
CalculatorAddOnly("0 / 0")
CalculatorAddOnly("5 ^ 3")
CalculatorAddOnly("-5 ^ 3")
CalculatorAddOnly("-8 ^ 3")
CalculatorAddOnly("-1 ^ 1")
CalculatorAddOnly("1 ^ 1")
CalculatorAddOnly("0 ^ 5")
CalculatorAddOnly("5 ^ 0")
CalculatorAddOnly("10 ^ -3")