10035 - Primary Arithmetic

10035 - Primary Arithmetic

I could've done it using mod%10 but I wanted to do it with arrays. 

#include

#include

#define N 10+1

int main() {

    

    /* 

     size_t strlen ( const char * str );

     Returns the length of the C string str.

     

     The length of a C string is determined by the terminating null-character: 

     A C string is as long as the number of characters between the beginning of the string and the terminating null character (without including the terminating null character itself).

     */

    

    int i=0, j=0;

    char inputa[N+1], inputb[N+1]; /* '\0' */

    int a[N], b[N];

    size_t na=0, nb=0; /* size_t is unsigned long */

    int carry=0;

    while(1) {

        scanf("%s %s", inputa, inputb);

        

        if ((inputa[0] == '0') && (inputb[0] == '0'))

            break;

        

        /* init */

        carry=0;

        

        for (i=0; i<N; i++) {

            a[i]=0;

            b[i]=0;

        }

        

        /* copy to integer arrays  */

        na = strlen(inputa);

        nb = strlen(inputb);

        

        j=N-na;

        for (i=0; i

            a[j++] = inputa[i] - '0';

        }

        

        j=N-nb;

        for (i=0; i

            b[j++] = inputb[i] - '0';

        }

        

        /* carry part */

        for (i=N-1; i>=0; i--) {

            if (a[i]+b[i] > 9) {

                carry++;

                a[i-1]++;

            }

        }

        

        /* print */

        if (carry == 0)

            printf("No carry operation.\n");

        else if (carry == 1)

        printf("1 carry operation.\n");

        else

        printf("%d carry operations.\n", carry);

    }

    return 0;

}