HammingCode(Generate&Correct)

//Prefer Running the Code in Console/Command Prompt
//This Program is to Generate Hamming Code for any Message to be sent by Receiver Or To check whether the Received Code is Correct or Not???

#include<iostream>
#include<string.h>
#include<math.h>
using namespace std;

int givePos(int n,int a[])
{
	int sum = 0;
	
	for(int i=0;i<n;i++)
	{
		sum += a[i]*pow(2,i);
	}
	return sum;
}

int changeBit(int x)
{
	if(x == 0)
	{
		return 1;
	}
	return 0; 
}

int rBit(int n,int a[],int x)
{
	int i = x,count = x,sum = 0;
	
	while(i <= n)
	{
		while(count--)
		{
			if(i>n)
			{
				break;
			}
			sum += a[i-1];
			i++;
		}
		count = x;
		i += x;
	}
	
	if(sum%2 == 0)
	{
		return 0;
	}
	return 1;
}

int main()
{
	int p,ch;
	
	while(1)
	{
		printf("Enter Choice:\n\n1.Sender\n2.Receiver\n3.Quit\n\nchoice: ");
		scanf("%d",&ch);
		
		if(ch == 1)
		{
			char s[1000];
			
			printf("\nEnter 'Message' for which you want Hamming Code :");
			scanf("%s",s);

			int count=1,l = strlen(s);

			while(1)
			{
				if(pow(2,count) >= l+count+1)
				{
					break;
				}
				count++;
			}
			
			printf("\n-> Redundant bits required = %d\n\n",count);

			int n = l + count,temp = l-1;

			int a[n];

			count = 0;
	
			for(int i=0;i<n;i++)
			{
				int t = pow(2,count) - 1;

				if(i != t)
				{
					a[i] = (int)s[temp] - 48;
					temp--;
				}
				else
				{
					a[i] = 0;
					count++;
				}
			}

			printf("-> Redundant bits are : (");

			for(int i=0;i<count;i++)
			{
				temp = pow(2,i);
				printf("r%d",temp);
						
				if(i != count-1)
				{
					printf(",");
				}
			}
			
			printf(") = (");

			for(int i=0;i<count;i++)
			{
				temp = pow(2,i) - 1;
				a[temp] = rBit(n,a,temp+1);
				printf("%d",a[temp]);

				if(i != count-1)
				{
					printf(",");
				}
			}
			
			printf(")\n\n");

			printf("-> Your Generated Hamming Code is : ");

			for(int i=n-1;i>=0;i--)
			{
				printf("%d",a[i]);
			}
			
			printf("\n\n");

			for(int i=0;i<172;i++)
			{
				printf("-");
			}
			printf("\n");
		}
		else if(ch == 2)
		{
			char s[1000];
			
			printf("\nEnter 'Hamming Code' You want to Check Error for: ");
			scanf("%s",s);

			int l = strlen(s),count = 1;

			while(1)
			{
				if(pow(2,count) >= l+1)
				{
					break;
				}
				count++;
			}
			
			int a[l],r[count];
			
			for(int i=0;i<l;i++)
			{
				a[i] = (char)s[l-i-1] - 48;
			}
			
			int error = 0,temp;

			printf("\n-> Redundant Bits are : (");

			for(int i=0;i<count;i++)
			{
				temp = pow(2,i);
				printf("r%d",temp);
				
				if(i != count-1)
				{
					printf(",");
				}
			}
			
			printf(") = (");
			
			for(int i=0;i<count;i++)
			{
				temp = pow(2,i) - 1;
				
				r[i] = rBit(l,a,temp+1);
				printf("%d",r[i]);

				if(i != count-1)
				{
					printf(",");
				}
				
				if(r[i] == 1)
				{
					error = 1;
				}
			}
			
			printf(")\n\n");
			
			if(error == 1)
			{
				int bit = givePos(count,r);
				printf("-> Your Message have error at %dth Position\n\n-> Corrected Message is : ",bit);
				
				for(int i=l-1;i>=0;i--)
				{
					if(i == bit-1)
					{
						a[i] = changeBit(a[i]);
					}
					printf("%d",a[i]);
				}
				printf("\n\n");
			}
			else
			{
				printf("-> No Error !!!\n\n");
			}
			
			for(int i=0;i<172;i++)
			{
				printf("-");
			}
			
			printf("\n");
		}
		else 
		{
			break;
		}
	}
}