#include <stdio.h>
#include <stdlib.h>
#include <string.h>

void afisare(int vector[201])
{
    for(int i = vector[0]; i > 0; i--)
        printf("%d ", vector[i]);

}

void afisare_vectori(int a[200], int b[200]){

    for(int i = a[0]; i > 0; i--)
        printf("%d ", a[i]);
    printf("\n");
    for(int i = b[0]; i > 0; i--)
        printf("%d ", b[i]);
    printf("\n");

}

void suma(int numar1[201], int numar2[201], int suma_mare[201])
{

    int t = 0, n;
    if(numar1[0] < numar2[0])
    {
        n = numar2[0];
        for(int i = numar1[0] + 1; i <= numar2[0]; i++)
            numar1[i] = 0;
    }
    else
    {
        n = numar1[0];
        for(int i = numar2[0] + 1; i <= numar1[0]; i++)
            numar2[i] = 0;
    }
    int i;
    for(i = 1; i <= n; i++)
    {
        int cifra = numar1[i] + numar2[i] + t;
        suma_mare[i] = cifra % 10;
        t = cifra/10;
    }
    if(t)
        suma_mare[i] = t;
    else
        i--;
    suma_mare[0] = i;
    for(i=numar1[0]; i>0; i--)
        printf("%d ",numar1[i]);
    printf("\n");
    for(i=numar1[0]; i>0; i--)
        printf("%d ",numar2[i]);
    printf("\n");
    afisare(suma_mare);

}

void diferenta(int numar1[201], int numar2[201], int diferenta_mare[201]){

    if(numar1[0] < numar2[0])
        diferenta(numar2, numar1, diferenta_mare);
    else{

        int i, t = 0;
        for(i = 1; i <= numar1[0]; i++){

            diferenta_mare[i] = numar1[i] - numar2[i] + t;
            if(diferenta_mare[i] < 0){

                diferenta_mare[i] += 10;
                t = -1;
            }
            else
                t = 0;
        }
        i--;
        while(i && !diferenta_mare[i])
            i--;
        if(i == 0){
            printf("0");
        }
        else{
            diferenta_mare[0] = i;
            for(i=numar1[0]; i>0; i--)
                printf("%d ",numar1[i]);
            printf("\n");
            for(i=numar1[0]; i>0; i--)
                printf("%d ",numar2[i]);
            printf("\n");
            afisare(diferenta_mare);
        }

    }

}

void inmultire(int a[200], int numar){
    if(numar == 0){
        printf("0");
        return 0;
    }
    for(int i=a[0]; i>0; i--)
        printf("%d ",a[i]);
    printf("\n");
    for(int i = 0; i < 2*a[0] - 2; i++)
        printf(" ");
    printf("%d", numar);
    printf("\n");
    int i, t = 0;
    for(i = 1; i <= a[0]; i++){

        a[i] = a[i] * numar + t;
        t = a[i] / 10;
        a[i] = a[i] % 10;
    }
    while(t){
        a[++a[0]] = t % 10;
        t /= 10;
    }
    afisare(a);
    printf("\n");

}


int main()
{

    int a[200] = {0}, b[200] = {0}, s[200] = {0}, d[200] = {0},scalar, chose, ok = 1;
    char x[200], y[200], z[200];
    printf("Primul numar = ");
    gets(x);
    printf("Al doilea numar = ");
    gets(y);
    a[0] = strlen(x);
    b[0] = strlen(y);
    for(int i = strlen(x) - 1; i >= 0; i--)
    {
        a[strlen(x) - i] = (int)(x[i] - '0');
    }
    for(int i = strlen(y) - 1; i >= 0; i--)
    {
        b[strlen(y) - i] = (int)(y[i] - '0');
    }
    int k;
    do{
        printf("\n<0>Iesire din program\n");
        printf("<1>Suma celor 2 numere\n");
        printf("<2>Diferenta celor 2 numere\n");
        printf("<3>Produsul unui numar oricat de mare cu o cifra\n");
        printf("<4>Afisare vectori\n");
        printf("Alege o optiune: ");
        scanf("%d", &k);
        switch(k){
            case 0: exit(0);
            case 1: suma(a, b, s); printf("\n");break;
            case 2: diferenta(a, b, d);printf("\n");break;
            case 3: printf("Introduceti scalarul: ");scanf("%d", &scalar);printf("Cu care dintre numere 1 sau 2?: ");scanf("%d", &chose);
                    while(ok){if(chose == 1){inmultire(a, scalar);break;}else if(chose == 2){inmultire(b,scalar);break;}else {printf("Alegeti unul dintre cele doua numere 1 sau 2!: ");scanf("%d", &chose);}}break;
            case 4:afisare_vectori(a, b);break;
            default: printf("Intoruceti una dintre optiunile mentionate!\n");
        }

    }while(k);

    return 0;
}