Cyclic Redundancy Check ( CRC ) in c++

What is CRC or Cyclicc Redundancy Check ?

The cyclic redundancy check (CRC) is a technique used to detect errors in digital data. CRC is a hash function that detects accidental changes to raw computer data commonly used 

in digital telecommunications networks and storage devices such as hard disk drives. 

Cyclic redundancy checks are simple to implement in hardware and can be easily analyzed mathematically.

this operation works like X-or gate operation . 

example:

subtraction process will works like X-or gate.

Implementation :

#include<bits/stdc++.h> using namespace std; int main() { char data1[100], key[] = "1101" ; int i, j, k; cout<<"enter the data : "; cin>>data1; int solen = strlen(data1); char data2[solen+3]; for(i=0; i<solen; i++) { data2[i]=data1[i]; } data2[i]='0'; data2[i+1]='0'; data2[i+2]='0'; data2[i+3]='\0'; cout<<"After input data : "<<endl; cout<<data1<<" "<<data2<<endl; for(i=0; i<solen; i++) { for(j=0; j<4; j++) { if(data2[i+j]==key[j]) { data2[i+j] = '0'; } else { data2[i+j] = '1'; } } k=0; for(j=1; data2[i+j]!= '1'; j++) { k++; } i+=k; } for(i=0; i<solen; i++) { data2[i]=data1[i]; } cout<<"After CRC : "<<endl; cout<<data1<<" "<<data2<<endl; return 0; }

Output:

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