#include <iostream>
#include <string>
#define N 10

using namespace std;

int* createMas();

int* set();

int compare(int a[], int b[]);

void swap(int** a, int** b);

int* difference(int a[], int b[]);

int* sum(int a[], int b[]);

void printMas(int a[]);

int main(){

    int * a = set();
    int * b = set();

    printMas(a);
    printMas(b);

    cout << "Difference: " << endl;
    int *c = difference(a,b);
    printMas(c);

    cout << "Sum: " << endl;
    c = sum(a,b);
    printMas(c);


    return 0;
}


int* createMas(){

    int *a =  new int [N];
    for(int i = 0; i < N; i++){
        a[i] = 0;
    }
    a[0] = 1;

    return a;
}

int* set(){

    string s;
    cout << " Please, enter value ";
    cin >> s;
    int *a =  createMas();
    int l = s.size() - 1;

    if (s[0] == '-'){
        a[0] = 0;
        s.erase(0,1);
    }
    l = s.size() - 1;

    for(int i = 0; l - i >= 0 ; i++){
        a[N-1-i] = s[l-i] - '0';
    }
    return a;
}

int compare(int a[], int b[]) {

    if ( a[0] == 0 && b[0] == 1 )
        return -1;

    if ( a[0] == 1 && b[0] == 0 )
        return 1;

    for(int i = 0; i < N; i++){
        if(a[i] > b[i]){
            return 1;
        }
        if(a[i] < b[i]){
            return -1;
        }

    }
    return 0;
}


void swap(int** a, int** b) {
    int *tmp = *a;
    *a = *b;
    *b = tmp;
}

int* diff_plus(int a[], int b[]){

    int *c = createMas();
    bool f = 0;
    if (compare(a,b) < 0){
        swap(a,b);
        f = 1;
    }
    for(int i = N - 1; i > 0; i--){
        c[i] = c[i] + (a[i] - b[i]);
        if (c[i] < 0){
            c[i] = c[i] + 10;
            c[i-1] = -1;
        }
    }
    if(f){
        swap(a,b);
        c[0] = 0;
    }

    return c;
}

int* difference(int a[], int b[]){
    bool a_sing = a[0],
         b_sing = b[0];
    int *c;
    if(a[0] == 1 && b[0] == 1){
        c = diff_plus(a, b);
    }
    else if(b[0] == 0){
        b[0] = 1;
        c = sum(a, b);
    }
    else{
        a[0] = 1;
        b[0] = 1;
        c = sum(a, b);
        c[0] = 0;
    }


    a[0] = a_sing;
    b[0] = b_sing;

    return c;
}

int* sum(int a[], int b[]){
    int *c = createMas();
    if(a[0] == 1 && b[0] == 1) {
        for(int i = N -1; i > 0; i--){
            c[i] = c[i] + a[i] + b[i];
            if (c[i] > 9){
                c[i-1] = 1;
                c[i] = c[i] - 10;
            }
        }
    }
    if(a[0] == 0 && b[0] == 0) {
        for(int i = N -1; i > 0; i--){
            a[0] = 1;
            b[0] = 1;
            c = sum(a, b);
            c[0] = 0;
            a[0] = 0;
            b[0] = 0;
        }
    }
    if(a[0] == 0 ^ b[0] == 0){
        bool a_sing = a[0],
             b_sing = b[0];

        a[0] = 1;
        b[0] = 1;
        if(compare(a, b) == 1){
            c = difference(a, b);
            c[0] = a_sing;
        }
        else if(compare(b, a) == 1){
            c = difference(b, a);
            c[0] = b_sing;
        }
        a[0] = a_sing;
        b[0] = b_sing;
    }
    return c;
}

void printMas(int a[]) {
    int i = 1;
    while (i < N && a[i] == 0)
        i++;

    if (i == N) {
        cout << "0" << endl;
        return ;
    }
    if (a[0] == 0){
        cout << "-";
    }
    while(i < N){
        cout << a[i];
        i++;
    }

    cout << endl;
}