Lecture "Recursion", exercise 1

[essepuntato]

Define a recursive function def exponentiation(base_number, exponent) for implementing the exponentiation operation. Test (by implementing the related test case) it on the following inputs: 3⁴, 17¹, and 2⁰.

[diegochillo]

def test_exponentiation(base_number,exponent,expected):
  result=exponentiation(base_number,exponent)
  return result==expected

def exponentiation(base_number,exponent):
  if not (exponent):
    return 1   
  else:
    return base_number * exponentiation(base_number, exponent - 1) 


print(test_exponentiation(3, 4, 81)) 
print(test_exponentiation(17, 1, 17)) 
print(test_exponentiation(2, 0, 1))

[SarahTew]

I wrote this and it does work, though not for negative exponents so I have it return a string saying the exponent is negative when that's an input. Is that right? Is there a way to make it work with negative exponents as well? Here is the link to PythonTutor if you want to see how it works.

def exponentiation(base_number, exponent):
    if exponent < 0:
        return "Negative Exponent!"    
    elif exponent == 0:
        return 1
    elif exponent == 1:
        return base_number
    else:  
        return base_number * exponentiation(base_number, exponent - 1)
            

print(exponentiation(3,4))
print(exponentiation(17,1))
print(exponentiation(2,0))
print(exponentiation(-2,3))
print (exponentiation(3,-3))

def test_exponentiation(base_number, exponent, expected):
    result = exponentiation(base_number, exponent)
    if result == expected:
        return True
    else:
        return False
        
print(test_exponentiation(3, 4, 81))
print(test_exponentiation(17, 1, 17))
print(test_exponentiation(2, 0, 1))

[SusannaPinotti]

def test_exponential(base_number, exponent, expected):
    result = exponential(base_number, exponent)
    if expected == result:
        return True
    else:
        return False

def exponential(base_number, exponent):
    if exponent == 0:
        return 1
    else:
        return base_number * (exponential(base_number, exponent -1))

print(test_exponential(3, 4, 81)) #returns True
print(test_exponential(17, 1, 17)) #returns True
print(test_exponential(2, 0, 1)) #returns True 

[dbrembilla]

#test
def test(base_number, exponent, expected):
    return expected == exponentiation(base_number, exponent)

#exponential function
def exponentiation(base_number, exponent):
    if exponent == 0:
        if base_number == 0:
            return "Impossible."
        elif base_number != 0:
            return 1
    elif exponent == 1:
        return base_number
    else:
        return base_number * exponentiation(base_number, exponent - 1)

print(test(17, 1, 17)) #returns True
print(test(3, 4, 81)) #returns True
print(test(2, 0, 1)) #returns True

[gabrielefiorenza]

def test_exponentiation (base_number,exponent, expected):
    result = exponentiation(base_number,exponent)
    return result == expected

def exponentiation(base_number,exponent):
    if not exponent:
        return 1
    else:
        return base_number * exponentiation(base_number, exponent-1)


print(test_exponentiation(3,4,81)) #returns True
print(test_exponentiation(17,1,17)) #returns True
print(test_exponentiation(2,0,1)) #returns True

[AlessandraFa]

def test_exponentiation(base_number, exponent, expected):
    return expected == exponentiation(base_number, exponent)


def exponentiation(base_number, exponent):
    if base_number == 0 and exponent == 0:
        return None
    elif exponent == 0:
        return 1
    elif exponent < 0:
        exponent = exponent * -1
        return 1/(base_number * exponentiation(base_number, exponent - 1))
    else:
        return base_number * exponentiation(base_number, exponent - 1)


print(test_exponentiation(3, 4, 81))   # True
print(test_exponentiation(17, 1, 17))  # True
print(test_exponentiation(2, 0, 1))    # True

[IlaRoss]

#tests
def test_exponentiation(base_number, exponent, expected):
    result = exponentiation(base_number, exponent)
    if result == expected:
        return True
    else:
        return False

#algorithm
def exponentiation(base_number, exponent):
    if exponent == 0:
        return 1
    elif exponent > 0:
        return base_number * exponentiation(base_number, exponent - 1)
    elif exponent < 0:
        return 1 / base_number * exponentiation(base_number, exponent + 1)

#test runs
a = test_exponentiation(3, 4, 81)
b = test_exponentiation(17, 1, 17)
c = test_exponentiation(2, 0, 1)

print(a)
print(b)
print(c)

[yunglong28]

# Test function

def test_exponentiation (base_number, exponent, expected):
    result = exponentiation (base_number, exponent)
    if result == expected:
        return True
    else:
        return False

# Recursive function for calculating a power

def exponentiation(base_number,exponent):
  if exponent == 0:
    return 1   
  else:
    return base_number * exponentiation(base_number, exponent - 1)


print (test_exponentiation (3, 4, 81))  #True
print (test_exponentiation (17,1,17))  #True
print (test_exponentiation (2, 0, 1))  #True

[LuisAmmi]

def test_exponentiation(base_n, exp, expected):
    result = exponentiation(base_n, exp)
    if result == expected:
        return True
    else:
        return False
        

def exponentiation(base_n, exp):
    if exp == 0:
        return 1
    else:
        return base_n * exponentiation(base_n, exp - 1)

print(test_exponentiation(3, 4, 81)). #true
print(test_exponentiation(17, 1, 17))
print(test_exponentiation(2, 0, 1))

[ChiaraCati]

def test_exp(base, exponent, expected):
    result = exp(base, exponent)
    if result == expected:
        return True
    else:
        return False


def exp(base, exponent):
    if exponent >= 0:  # for exponent
        if exponent == 1:
            return base
        elif exponent > 1:
            return base * exp(base, exponent - 1)
        else:
            return 1
    if exponent < 0:
        positive = 1 / base

        if exponent == -1:
            return positive
        else:
            return round(positive * exp(base, exponent + 1), 2)



print(test_exp(3, 4, 81))
print(test_exp(17, 1, 17))
print(test_exp(2, 0, 1))
print(test_exp(4, -2, 0.06))

[edoardodalborgo]

def test_exponentiation(base_number, exponent, expected):
    result = exponentiation(base_number, exponent)
    if result == expected:
        return True
    else:
        return False

def exponentiation(base_number, exponent):
    if exponent == 0:
        return 1
    else:
        return base_number * exponentiation(base_number, exponent - 1)

print(test_exponentiation(3, 4, 81))
print(test_exponentiation(17, 1, 17))
print(test_exponentiation(2, 0, 1))

[AleRosae]

def test_exp(base_number, exponent, expected):
    return expected == exponentiation(base_number, exponent)

def exponentiation (base_number, exponent):
    if exponent == 0:
        return 1
    elif exponent == 1:
        return base_number
    elif exponent<0:
        return 1/(base_number)*(exponentiation(base_number,exponent+1 ))
    else:
        return base_number * exponentiation(base_number, exponent-1)

print(test_exp(3,4,81))
print(test_exp(17,1,17))
print(test_exp(2,0,1))
print(test_exp(2,-4,0.0625))

[fcagnola]

def test_2_parameter(function, parameter1, parameter2, expected):
    result = function(parameter1, parameter2)
    return result == expected

def exponentiation(base, exponent):
    if exponent < 0:  # if exponent is negative do not run function, but return error message
        return "exponent must be a positive integer"
    if exponent == 0: # base case, anything to the power of 0 returns 1
        return 1
    else:  # recursive function, returns multiplication of base * each run's result
        return base * exponentiation(base, exponent-1)

print(test_2_parameter(exponentiation,3,4,81)) # returns True
print(test_2_parameter(exponentiation,17,1,17)) # returns True
print(test_2_parameter(exponentiation,2,0,1)) # returns True

[SofiBar]

def test_exponentiation(base_number, exponent, expected):
    return exponentiation(base_number, exponent) == expected


def exponentiation(base_number, exponent):
    if exponent == 1:
        return base_number
    elif exponent == 0:
        return 1
    elif exponent < 0:
        return 1/exponentiation(base_number, -1*exponent)
    else:
        return base_number*exponentiation(base_number, exponent-1)


print(test_exponentiation(3, 4, 81))
print(test_exponentiation(17, 1, 17))
print(test_exponentiation(2, 0, 1))

[giorgiasampo]

def` test_exponentiation(base_number, exponent, expected):
    result = exponentiation(base_number, exponent)
    return result == expected


def exponentiation(base_number, exponent):
    if exponent == 0:
        return 1
    else:
        return base_number*exponentiation(base_number, exponent-1)


print (test_exponentiation(3, 4, 81))
print (test_exponentiation(17, 1, 17))
print (test_exponentiation(2, 0, 1))

[vanessabonanno]

def test_exponentiation(num, exp, expected):
    result = exponentiation(num, exp)
    if result == expected:
        return True
    else:
        return False


def exponentiation(num, exp):
    if exp == 0:
        return 1  # base condition
    elif exp == 1:
        return num
    elif exp > 0:
        return num * exponentiation(num, exp - 1)
    elif exp < 0:
        return 1 / num * exponentiation(num, exp + 1)
    else:
        return "Wrong input"


print(test_exponentiation(3, 4, 81))    # True
print(test_exponentiation(17, 1, 17))   # True
print(test_exponentiation(2, 0, 1))     # True

[laurentfintoni]

def test_exponentation(int_1, int_2, expected):
    result = exponentation(int_1, int_2)
    if result == expected:
        return True
    else: 
        return False 

def exponentation(int_1, int_2):
    if int_2 == 0:
        return 1
    else:
        return int_1 * exponentation(int_1, int_2 - 1)

print(test_exponentation(3, 4, 81))
print(test_exponentation(17, 1, 17))
print(test_exponentation(2, 0, 0))

[AlessandroBertozzi]

# Test case for the algorithm
def test_exponentiation(int_1, int_2, expected):
    result = exponentiation(int_1, int_2)
    if expected == result:
        return True
    else:
        return False


# Code of the algorithm
def exponentiation(int_1, int_2):
    if int_2 == 0:
        return 1
    else:
        return int_1 * exponentiation(int_1, int_2 - 1)



print(test_exponentiation(3, 4, 81))
print(test_exponentiation(17, 1, 17))
print(test_exponentiation(2, 0, 1))

[GiuliaMenna]

def test_exp(base_number, exponent,expected):
    result = exp(base_number, exponent)
    if expected == result:
        return True
    else:
        return False

def exp(base_number, exponent):
    if exponent == 0:
        return 1
    else:
        return base_number * exp(base_number, exponent - 1)
    return result

print(test_exp(3,4,81))
print(test_exp(17,1,17))
print(test_exp(2,0,1))