C program for implementing Restoring Division algorithm

/*Program for implementing Restoring Division algorithm.*/

#include <stdio.h>

#include <conio.h>

#include <math.h>

int a=0,b=0,c=0,com[5]={1,0,0,0,0},s=0;

int anum[5]={0},anumcp[5] ={0},bnum[5]={0};

int acomp[5]={0},bcomp[5]={0},rem[5]={0},quo[5]={0},res[5]={0};

void binary(){

     a = fabs(a);

     b = fabs(b);

     int r, r2, i, temp;

     for(i = 0; i < 5; i++){

           r = a % 2;

           a = a / 2;

           r2 = b % 2;

           b = b / 2;

           anum[i] = r;

           anumcp[i] = r;

           bnum[i] = r2;

           if(r2 == 0){

                bcomp[i] = 1;

           }

           if(r == 0){

                acomp[i] =1;

           }

     }

   //part for two's complementing

   c = 0;

   for( i = 0; i < 5; i++){

           res[i] = com[i]+ bcomp[i] + c;

           if(res[i]>=2){

                c = 1;

           }

           else

                c = 0;

           res[i] = res[i]%2;

     }

   for(i = 4; i>= 0; i--){

     bcomp[i] = res[i];

   }

}

void add(int num[]){

     int i;

     c = 0;

     for( i = 0; i < 5; i++){

           res[i] = rem[i]+ num[i] + c;

           if(res[i]>=2){

                c = 1;

           }

           else

                c = 0;

           res[i] = res[i]%2;

     }

     for(i = 4; i>= 0; i--){

           rem[i] = res[i];

           printf("%d",rem[i]);

     }

     printf(":");

     for(i = 4; i>= 0; i--){

           printf("%d",anumcp[i]);

     }

}

void shl(){//for shift left

     int i;

     for(i = 4; i > 0  ; i--){//shift the remainder

           rem[i] = rem[i-1];

     }

     rem[0] = anumcp[4];

     for(i = 4; i > 0  ; i--){//shift the remtient

           anumcp[i] = anumcp[i-1];

     }

     anumcp[0] = 0;

     printf("\nSHIFT LEFT: ");//display together

     for(i = 4; i>= 0; i--){

           printf("%d",rem[i]);

     }

     printf(":");

     for(i = 4; i>= 0; i--){

           printf("%d",anumcp[i]);

     }

}

void main(){

     clrscr();

     int i;

     printf("\t\tRESTORING DIVISION ALGORITHM");

     printf("\nEnter two numbers to multiply: ");

     printf("\nBoth must be less than 16");

     //simulating for two numbers each below 16

     do{

           printf("\nEnter A: ");

           scanf("%d",&a);

           printf("Enter B: ");

           scanf("%d",&b);

     }while(a>=16 || b>=16);

     printf("\nExpected Quotient = %d", a/b);

     printf("\nExpected Remainder = %d", a%b);

     if(a*b <0){

           s = 1;

     }

     binary();

     printf("\n\nUnsigned Binary Equivalents are: ");

     printf("\nA = ");

     for(i = 4; i>= 0; i--){

           printf("%d",anum[i]);

     }

     printf("\nB = ");

     for(i = 4; i>= 0; i--){

           printf("%d",bnum[i]);

     }

     printf("\nB'+ 1 = ");

     for(i = 4; i>= 0; i--){

           printf("%d",bcomp[i]);

     }

     printf("\n\n-->");

     //division part

     shl();

     for(i=0;i<5;i++){

           printf("\n-->"); //start with subtraction

           printf("\nSUB B: ");

           add(bcomp);

           if(rem[4]==1){//simply add for restoring

                printf("\n-->RESTORE");

                printf("\nADD B: ");

                anumcp[0] = 0;

                add(bnum);

           }

           else{

                anumcp[0] = 1;

           }

           if(i<4)

                shl();

     }

     printf("\n----------------------------");

     printf("\nSign of the result = %d",s);

     printf("\nRemainder is = ");

     for(i = 4; i>= 0; i--){

           printf("%d",rem[i]);

     }

     printf("\nQuotient is = ");

     for(i = 4; i>= 0; i--){

           printf("%d",anumcp[i]);

     }

getch();

}