blkChain = []

def get_last_blk_chain_value():

return blkChain[-1]

def add_value(txn_amt, last_txn_value=[1]):

""" test comment """

blkChain.append([last_txn_value, txn_amt])

# print(blkChain)

def get_transaction_amt():

return float(input("enter amt: "))

def get_user_choice():

return input('Choice: ')

def print_blkchain_elements():

for block in blkChain:

print(block)

def manipulate():

blkchain_len = len(blkChain)

if blkchain_len > 0:

idx_value = int(input("which idx you want to change ? length of chain is: " + str(blkchain_len) ))

if idx_value <= blkchain_len:

blkChain[idx_value - 1] = [float (input("Enter your value: "))]

print(blkChain)

def verify_chain1():

if len(blkChain) > 0:

loop_idx = 0

for block in blkChain:

#print("current block ",block ," idx value ", loop_idx, " current at loop idx ", block[0] , " previous block ", blkChain[loop_idx-1])

if loop_idx ==0 :

loop_idx +=1

continue

elif block[0] != blkChain[loop_idx -1]:

print("bad block chain at idx ", block[0] , blkChain[loop_idx-1])

print("bad block chain at idx ", loop_idx)

loop_idx += 1

#break

def verify_chain():

if len(blkChain) > 0:

loop_idx = 0

for block in blkChain:

#print("current block ",block ," idx value ", loop_idx, " current at loop idx ", block[0] , " previous block ", blkChain[loop_idx-1])

if loop_idx ==0 :

loop_idx +=1

continue

elif block[0] != blkChain[loop_idx -1]:

return False

loop_idx += 1

return True

#break

while True:

print('Select 1 2 m v q for add new block: ')

user_input = get_user_choice()

if user_input == '1':

if len(blkChain) >= 1:

add_value(get_transaction_amt(), get_last_blk_chain_value())

else:

add_value(get_transaction_amt())

elif user_input == '2':

print_blkchain_elements()

elif user_input == 'q':

break

elif user_input == 'm':

manipulate()

elif user_input == 'v':

print(" Blkcain valid: ",verify_chain() )

else:

print('invalid input')