#include <stdio.h>
#include <stdlib.h>
#define N 8

void add(int*, int*, int*);
void subtract(int*, int*, int*);
void multiply(int*, int, int*);
void divide(int*, int, int*);
void toComp(int*, int*);  // 轉補數
void absv(int*, int*);    // 轉絕對值
void print(int*);         // 顯示大整數

int main(void) {
int a[] = {0, 0, 0, 1234, 5678, 9910, 1923, 1124};
int b[] = {9999, 9999, 9999, 9999, 9999, 9999, 9999, 9901}; // -99
    int c1[N], c2[N], c3[N], c4[N] = {0};
add(a, b, c1);       print(c1);
subtract(a, b, c2);  print(c2);
multiply(a, -3, c3); print(c3);
divide(a, -3, c4);   print(c4);
return 0;
}
void add(int* a, int* b, int* c) {
if(b[0] == 9999) {
int comp[N] = {0};
toComp(b, comp);
subtract(a, comp, c);
} else {
int i, carry = 0;
for(i = N - 1; i >= 0; i--) {
c[i] = a[i] + b[i] + carry;
if(c[i] < 10000) {
carry = 0;
} else { // 進位
                c[i] = c[i] - 10000;
carry = 1;
}
}
}
}
void subtract(int* a, int* b, int* c) {
if(b[0] == 9999) {
int comp[N] = {0};
toComp(b, comp);
add(a, comp, c);
} else {
int i, borrow = 0;
for(i = N - 1; i >= 0; i--) {
c[i] = a[i] - b[i] - borrow;
if(c[i] >= 0) {
borrow = 0;
} else { // 借位
                c[i] = c[i] + 10000;
borrow = 1;
}
}
}
}
void multiply(int* a, int b, int* c) { // b 為乘數
    int op1[N] = {0}; absv(a, op1);
int op2 = abs(b);
int i, tmp, carry = 0;
for(i = N - 1; i >= 0; i--) {
tmp = op1[i] * op2 + carry;
c[i] = tmp % 10000;
carry = tmp / 10000;
}
if((a[0] == 9999 && b > 0) || (a[0] == 0 && b < 0)) {
toComp(c, c);
}
}
void divide(int* a, int b, int *c) {  // b 為除數
    int op1[N] = {0}; absv(a, op1);
int op2 = abs(b);
int i, tmp, remain = 0;
for(i = 1; i < N; i++) {
tmp = op1[i] + remain;
c[i] = tmp / op2;
remain = (tmp % op2) * 10000;
}
if((a[0] == 9999 && b > 0) || (a[0] == 0 && b < 0)) {
toComp(c, c);
}
}
void toComp(int* src, int* comp) {
int j;
for(j = 0; j < N; j++) {
comp[j] = 9999 - src[j];
}
comp[N - 1] += 1;
}
void absv(int* src, int* op) {
if(src[0] == 9999) {
toComp(src, op);
} else {
int i;
for(i = 0; i < N; i++) {
op[i] = src[i];
}
}
}
void print(int* c) {
int v[N] = {0}; absv(c, v);
if(c[0] == 9999) {
printf("-");
}
int isDropZero = 1;
int i;
for(i = 0; i < N; i++) {
char s[5] = {'\0'};
sprintf(s, "%04d", v[i]);
if(isDropZero) {
int j;
for(j = 0; s[j] == '0' && j < 4; j++);
if(j < 4) {
isDropZero = 0;
for(; j < 4; j++) {
printf("%c", s[j]);
}
} else if(i == N - 1) {
printf("0");
}
} else {
printf(s);
}
}
printf("\n");
}