Booth's Algorithm - C Implementation

 #include <stdio.h>  
 #define WORD 4  
 #define VERBOSE 1 //0  
 /*  
  * 02 DEC 2011  (CSC2304)
  * Implementation of the Booth's Algorithm.  
  */  
 void twosComplementAddition(char[], char[]);  
 void rightShift(char[], char);  
 void addition(char[], char[]);  
 char* twosComplementMultiplication(char M[], char Q[]) {  
   char C;  
   char *A = (char*) malloc(sizeof(char)*(2 * WORD + 1));  
   char processedQ[WORD+ 1];  
   char Q0, Q_1 = '0';  
   int i, j;  
   strcpy(A, "0000");  
   if (VERBOSE) {  
     printf("\n  A  |  Q  |  M  |");  
     printf("\n  %s  |  %s  |  %s  |  Initial", A, Q, M);  
     printf("\n-------------------------------------------------------------");  
   }  
   for (i = 0, j = 1; i < WORD; i++, j++) {  
     Q0 = Q[WORD - 1];  
     if (VERBOSE) {  
       printf("\n  %s  |  %s  |  %s  |  Cycle %d", A, Q, M, j);  
     }  
     if (Q0 == '0' && Q_1 == '1') {  
       addition(A, M);  
       if (VERBOSE) {  
         printf("\n  %s  |  %s  |  %s  |  Addition", A, Q, M);  
       }  
     } else {  
       if (Q0 == '1' && Q_1 == '0') {  
         twosComplementAddition(A, M);  
         if (VERBOSE) {  
           printf("\n  %s  |  %s  |  %s  |  Two's Complement", A, Q, M);  
         }  
       }  
     }  
     Q_1 = Q[WORD - 1];  
     rightShift(Q, A[WORD - 1]);  
     rightShift(A, A[0]);  
     if (VERBOSE) {  
       printf("\n  %s  |  %s  |  %s  |  Right Shift", A, Q, M);  
       getch();  
     }  
     printf("\n-------------------------------------------------------------");  
   }  
   strcat(A, Q);  
   return A;  
 }  
 void rightShift(char reg[], char bit) {  
   int i;  
   for (i = WORD - 1; i > 0; i--) {  
     reg[i] = reg[i - 1];  
   }  
   reg[0] = bit;  
 }  
 void addition(char A[], char M[]) {  
   int i;  
   char c = '0';  
   for (i = WORD - 1; i >= 0; i--) {  
     if (A[i] == '0' && M[i] == '0') {  
       A[i] = c;  
       c = '0';  
     } else {  
       if ((A[i] == '1' && M[i] == '0') || (A[i] == '0' && M[i] == '1')) {  
         if (c == '0') {  
           A[i] = '1';  
         } else {  
           A[i] = '0';  
         }  
       } else {  
         if (A[i] == '1' && M[i] == '1') {  
           A[i] = c;  
           c = '1';  
         }  
       }  
     }  
   }  
 }  
 void twosComplementAddition(char A[], char M[]) {  
   int i;  
   char temp[WORD + 1];  
   for (i = 0; i < WORD; i++) {  
     if (M[i] == '0') {  
       temp[i] = '1';  
     } else {  
       temp[i] = '0';  
     }  
   }  
   temp[WORD] = '\0';  
   addition(temp, "0001");  
   addition(A, temp);  
 }  
 int main() {  
   char QQ[WORD + 1];  
   char M[WORD + 1];  
   char Q[WORD + 1];  
   char *result;  
   printf("\nBooth's Algorithm");  
   printf("\n*****************");  
   printf("\nEnter M: ");  
   scanf("%s", M);  
   printf("\nEnter Q: ");  
   scanf("%s", Q);  
   strcpy(QQ, Q);  
   result = twosComplementMultiplication(M, Q);  
   printf("\n%s * %s = %s", M, QQ, result);  
   printf("\n");  
   return 0;  
 }