高精度减法

#include
using namespace std;

int n1[1005], n2[1005], ans[1005], n, m;
char s1[1005], s2[1005];

void func(int *n1, int *n2, int n, int m) {
    for (int i = 0; i <= n; i++) {
        for (int j = 0; j <= m; j++) {
            if (n1[i] < n2[i]) {
                n1[i + 1]--;
                n1[i] += 10;
            }
            if (n1[n] == n2[n]) {
                n--;
            }
         ans[i] = n1[i] - n2[i];
        }
    }
    for (int i = n; i > 0; i--) {
        cout << ans[i];
    }
    cout << endl;
}

int main() {
    cin >> n >> m;
    cin >> s1 >> s2;
    for (int i = 0, j = n; i <= n; j--, i++) {
        n1[i] = s1[j] - '0';
    }
    for (int i = 0, j = m; i <= m; i++, j--) {
        n2[i] = s2[j] - '0';
    }
    if (n > m) {
        func(n1, n2, n, m);
    }else if (n == m) {
        for (int i = n; i >= 0; i--) {
            if (n1[i] > n2[i]) {
                func(n1, n2, n, m);
                break;
            } else if (n1[i] < n2[i]){
                cout << "-";
                func(n2, n1, n, m);
                break;
            } else {
                continue;
            }
        }
    } else {
        cout << "-";
        func(n2, n1, m, n);
    }
    return 0;
}