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‎2DimentionalParityCheck.py

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#!/usr/bin/env python
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# coding: utf-8
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# In[10]:
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def testing(reciever,div=5):
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message=str()
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length=len(reciever)
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#removing last column parity
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col = reciever[length-div:]
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reciever = reciever[:length-div]
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#checking error at parity in rows(added in middle by sender) and then removing
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row=[]
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row_count=0
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while(reciever):
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chunk = reciever[:div]
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old_parity=int(reciever[div])
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reciever = reciever[div+1:]
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message+=chunk
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sum_chunk=0
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for i in range(div):
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sum_chunk += int(chunk[i])
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if old_parity != (sum_chunk%2):
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row.append(row_count)
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row_count+=1
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print("Error in row_parity at",row)
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#checking parity in columns
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col_len=len(message)//div
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col_parity=[]
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for j in range(div):
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sum_chunk=0
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for i in range(col_len):
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sum_chunk += int(message[i*div+j])
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if int(col[j]) != (sum_chunk%2):
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col_parity.append(j)
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print("Error in col_parity at",col_parity)
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print("message received",message)
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if len(row)==0 and len(col_parity)==0:
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print("\nThere is no any error.")
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else:
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for i in range(len(row)):
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idx=row[i]*div+col_parity[-(i+1)]
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print("error found in the message at index",idx)
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if message[idx]==0:
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message=message[:idx]+'1'+message[idx+1:]
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else:
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message=message[:idx]+'0'+message[idx+1:]
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print("\nMessage after correcting at index",idx,"is",message)
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print("\nFinal message is",message)
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# In[11]:
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# def test(sender,reciever,div=4):
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# length=len(reciever)
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# #removing last column parity
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# send = sender[length-div:]
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# rec = reciever[length-div:]
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# #testing row parity
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# column_len=(length-div)//(div+1) # after removing last column parity
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# row=[]
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# for i in range(1,column_len):
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# x=i*(div+1)-1
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# if sender[x]!=reciever[x]:
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# row.append(i-1)
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# #testing column parity
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# col=[]
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# for i in range(div):
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# if send[i]!=rec[i]:
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# col.append(i)
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# idx=(div+1)*(row[0])+col[0]
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# print("row error is", row[0]+col[0])
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# if reciever[row[0]+col[0]]==0:
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# reciever=reciever[:idx]+'1'+reciever[idx+1:]
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# else:
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# reciever=reciever[:idx]+'0'+reciever[idx+1:]
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# print(reciever)
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# In[12]:
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def addingParity(string,div=5):
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message=str()
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#adding parity in rows format
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while(string):
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chunk = string[:div]
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string = string[div:]
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message+=chunk
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sum_chunk=0
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if len(chunk)==div:
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for i in range(div):
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sum_chunk += int(chunk[i])
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#parity adding
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message+=str(sum_chunk%2)
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else:
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for i in range(div-len(chunk)): #padding zeros
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message+='0'
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for i in range(len(chunk)):
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sum_chunk += int(chunk[i])
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#parity adding
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message +=str(sum_chunk%2)
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#adding parity in columns format
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column_len=len(message)//(div+1)
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for i in range(div):
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sum_column=0
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for j in range(column_len):
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sum_column += int(message[i+(div+1)*j])
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message += str(sum_column%2)
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return message
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# In[13]:
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if __name__=='__main__':
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input_message=input("\nEnter binary code for sending a message ")
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sender_message=addingParity(input_message)
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print("sender message ",sender_message)
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input_test=input("\nEnter binary code for testing of message ")
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# reciever_message=addingParity(input_test)
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# print("reciever message ",reciever_message)
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print("\nTesting result is here.......")
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# test(sender_message,reciever_message)
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testing(input_test)
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# In[14]:
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rec='01011110011001101010010101001'
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se='01011110001001001011010101001'
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mSenDer='01011100010100111010'
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#works only for diagoal [in case of more than 1 bit error]
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#It always corrects 1 bit error
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‎CheckSum.py

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#!/usr/bin/env python
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# coding: utf-8
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# In[1]:
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def binSum(chunk1,chunk2,div=8):
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st=bin(int(chunk1,2)+int(chunk2,2))
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if len(st)==div+3: #for removing first 0b from binay code 0bxxxxxx
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carry='1'
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st1=st[3:]
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st= binSum(st1,carry)
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return st
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else:
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return st[2:]
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# In[2]:
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def findCheckSum(message,div=8):
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mess_len=len(message)
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temp=message[:div]
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message=message[div:]
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for i in range((mess_len//div)-1):
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temp=binSum(temp,message[:div])
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message=message[div:]
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checkSum=temp
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#for taking compliment of check_sum
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for i in range(len(checkSum)):
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if checkSum[i]=='0':
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checkSum=checkSum[:i]+'1'+checkSum[i+1:]
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else:
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checkSum=checkSum[:i]+'0'+checkSum[i+1:]
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return checkSum
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# In[3]:
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def paddingZeros(message,div=8):
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if (len(message)%div!=0):
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for i in range(len(message)%div):
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message+='0'
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return message
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# In[6]:
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10011001111000100010010010000100
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# In[5]:
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if __name__=='__main__':
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#sender side
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send_message=input("enter sender message ")
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sender_check_sum=findCheckSum(paddingZeros(send_message))
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print("check sum of sender",sender_check_sum)
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#reciever side checking
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rec_message=input("enter recieved message ")
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rec_check_sum=findCheckSum(paddingZeros(rec_message))
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# st=bin(int(sender_info,2)+int(reciever_info,2))
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if (sender_check_sum==rec_check_sum):
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print("\nNo error")
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else:
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print("\nerror is present")
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‎CyclicRedundancyCheck.py

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#!/usr/bin/env python
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# coding: utf-8
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# In[47]:
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def divisionEx_OR(divisor,dividend):
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divisor_len=len(divisor)
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temp_remind=dividend[:divisor_len]
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while(True):#performing devision using Ex-OR operation.....
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temp=''
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for i in range(divisor_len): #Ex-OR operation
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if divisor[i]=='0' and temp_remind[i]=='0':
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temp+='0'
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elif divisor[i]=='1' and temp_remind[i]=='1':
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temp+='0'
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else:
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temp+='1'
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while(temp): #removing 0's from starting of the reminder
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if temp[0]=='0':
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temp=temp[1:]
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else:
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break
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if (len(dividend)+ len(temp) >=divisor_len):
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while(len(temp)<divisor_len): #for adding 0/1's from dividend to temp_reminder
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temp+=dividend[0]
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dividend=dividend[1:]
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else:
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reminder=temp
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break
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temp_remind=temp
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return reminder
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# In[48]:
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import numpy as np
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parity_gen=input("Enter the parity generato binar code ")
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mess=input("Enter the message for sending to reciever ")
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for i in range(len(parity_gen)-1):
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mess+='0'
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print("message after padding 0's before appliying CRC ",mess)
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#changing var_names......
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divisor=parity_gen; dividend=mess;
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reminder=divisionEx_OR(divisor,dividend)
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print("reminder after division (in the sender side)",reminder)
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# In[49]:
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#for replacing 0's by reminder that are added before applying CRC
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mess=mess[:len(mess)-len(reminder)]+reminder
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print("message, after replacing 0's by reminder that are added before applying CRC, is",mess)
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# In[50]:
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#reciever side CRC
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reminder_new=divisionEx_OR(divisor,mess)
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print("reminder after division (in reciever side)",reminder_new)
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if sum(int(x) for x in reminder_new)==0:
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print("There is no any error.")
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else:
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print("There is some error.")
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# In[52]:
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#error
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11001
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1010101010
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#no any error
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10011
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1101011111
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