Binary Add and Substraction

//////////////////////////////////////////////////////////////////////
////  This program add and substract two binary  numbers
       Taking the Input as a decimal number                 ///////
//////////////////////////////////////////////////////////////////////////


# include<stdio.h>
# include<conio.h>
# include<stdlib.h>

///////////////////////////////////////////////////////////////////////
///////////         programmer :  Harsh chandra      //////////////
/////////////////////////////////////////////////////////////////////

void binaryadd(int,int*,int*,int); /* funtion to add to binay numbers */
int a[8],b[8],c[8];  /* as we want 8 bits , here extern data type is required */
void main()
{   clrscr();
	 int n1,n2,i=0,carry=0,*m,*n,k,x,y,d[8]={1,0,0,0,0,0,0,0};
	 char op;
	 gotoxy(1,6);printf("Enter 1st Numbers :");
	 scanf("%d",&n1);
	 gotoxy(1,7);printf("Enter 2nd Numbers :");
	 scanf("%d",&n2);
	 oper: /* label to return back if user gives wrong operator */
	 gotoxy(1,11);printf("            ");
	 gotoxy(1,8);printf("\nEnter the operator(+,-) :");
	 op=getch();
	 x=n1;  /* for future refence in case of substraction */
	 y=n2;
	if(op =='+' || op=='-')
{	 while(n1!=0)   /* converting 1st number to its binary equivalent */
	 {  a[i]=n1 % 2;
		 n1/=2;
		 i++;
	 }
	 /* printing 1st number */
	 printf("\nThe binary of %d is : ",x);
	 for(k=7;k>=0;k--)
	 printf("%d",a[k]);
	 printf("\n");


	 i=0;
	  while(n2!=0)
	 {  b[i]=n2 % 2;    /* converting 2nd number to its binary equivalent */
		 n2/=2;
		 i++;
	 }

		/* printing binary of 2nd number */

	 printf("\nThe binary of %d number is :",y);
	 for(k=7;k>=0;k--)
	 printf("%d",b[k]);
	 printf("\n");
}
	 switch(op)
	 {  case '+':
		 i=0;
		 m=a;
		 n=b;
		 carry=0;
		 binaryadd(i,m,n,carry); /*function called for binary add */
		 printf("\nThe addition is :");
		 for(i=7;i>=0;i--)
		 {  printf("%d",c[i]);
		 }
		 break;
		 case '-':
		for(i=0;i<=7;i++)
		{  if(b[i]==0)
			b[i]=1;        /* 1's complement */
			else
			b[i]=0;
		}
		printf("\nThe 1's complement of %d is : ",y);
		for(i=7;i>=0;i--)
		printf("%d",b[i]);
		i=0;
		m=b;
		n=d;
		carry=0;
		binaryadd(i,m,n,carry); /* called for 2's complement */
		printf("\nThe 2's complement of %d is : ",y);
		for(i=7;i>=0;i--)
		printf("%d",c[i]);
		for(i=0;i<=7;i++)
		b[i]=c[i];
		i=0;
		m=a;
		n=b;
		carry=0;
		binaryadd(i,m,n,carry);
		if(x>y)
		{ printf("\nThe substaction is : ");
		  for(i=7;i>=0;i--)
		  printf("%d",c[i]);
		}
		if(x < y)
		{  for(i=7;i>=0;i--)
			{    if(c[i]==0)
				  c[i]=1;
				  else
				  c[i]=0;
			}
			i=0;
			m=c;
			n=d;
			carry=0;
			binaryadd(i,m,n,carry);/* again 2's complement for negative answers */
			printf("\nThe subsraction is : ");
			printf("-");
			for(i=7;i>=0;i--)
			printf("%d",c[i]);
		}
		 exit(0);
		break;
		default:
		gotoxy(1,11);printf("WRONG OPTION");
		getch();
		goto oper;

	 }
	 getch();
}



void binaryadd(int i,int *m,int *n,int carry)
{     if(*m==1 && *n==1 && carry==1)
	  {  c[i]=1;
		  carry=1;
	  }
		if(*m==1 && *n==1 && carry==0)
	  {  c[i]=0;
		 carry=1;
	  }
	  if(*m==0 && *n==1 && carry==0)
	  {  c[i]=1;
		 carry=0;
	  }
	  if(*m==0 && *n==1 && carry==1)
	  {  c[i]=0;
		 carry=1;
	  }
	  if(*m==1 && *n==0 && carry==0)
	  {  c[i]=1;
	carry=0;
	  }
	  if(*m==1 && *n==0 && carry==1)
	  {  c[i]=0;
	carry=1;
	  }
	  if(*m==0 && *n==0 && carry==0)
	  {  c[i]=0;
	carry=0;
	  }
	  if(*m==0 && *n==0 && carry==1)
	  {  c[i]=1;
	carry=0;
	  }

	  i++;
	  m++;
	  n++;
	  if(i<=8)                  /* Base value of recursion */
	  binaryadd(i,m,n,carry);  /* recursion till  we reach 8 bit of number */
}