Cấu trúc dữ liệu Đa thức bằng mảng

#include <stdio.h>
#include <conio.h>
#include <malloc.h>

#define Max 9
typedef int DaThuc[Max];

void ktRong(DaThuc &dt){
    for (int i=0;i<Max;i++)
        dt[i]=0;

}
void them(int hs,int sm, DaThuc &dt){
    dt[sm]=hs;
}
void congDT(DaThuc dt1,DaThuc dt2,DaThuc &dt3)
{
    for(int i=0;i<Max;i++)
        dt3[i]=dt1[i]+dt2[i];
}
void truDT(DaThuc dt1,DaThuc dt2,DaThuc &dt3)
{
    for(int i=0;i<Max;i++)
        dt3[i]=dt1[i]-dt2[i];
}
void inDT(DaThuc dt){
    for(int i=Max-1;i>=0;i--){
        if (dt[i]!=0){
           if (i==1)
             printf("%dx",dt[i]);
           else if (i==0)
             printf("%d",dt[i]);
           else
             printf("%dx^%d",dt[i],i);

            for(int j = i-1;j>=0;j--){
                    if (dt[j]<0)
                        break;
                    if (dt[j]>0){
                        printf("+");
                        break;
                    }
            }


        }
    }
}

void nhanDT(DaThuc dt1,DaThuc dt2,DaThuc &dt3){
    for (int i=0;i<Max-1;i++){
        if (dt1[i]!=0){
            DaThuc t;
            ktRong(t);
            for (int j = 0;j<Max-1;j++){
                if (dt2[j]!=0){
                    int hs = dt1[i]*dt2[j];
                    int sm = i + j;
                    them(hs,sm,t);
                }
            }
            congDT(t,dt3,dt3);
        }
    }
}
int main(){
     DaThuc dt1,dt2;
    ktRong(dt1);
    ktRong(dt2);


    them(2,0,dt1);
    them(3,1,dt1);
    them(6,4,dt1);
    them(6,1,dt2);
    them(10,2,dt2);
    printf("da thuc 1: ");
    inDT(dt1);
    printf("\n");
    printf("da thuc 2: ");
    inDT(dt2);

    DaThuc dt3;
    ktRong(dt3);
    congDT(dt1,dt2,dt3);
    printf("\nda thuc 3: ");
    inDT(dt3);

    DaThuc dt4;
    ktRong(dt4);
    truDT(dt1,dt2,dt4);
    printf("\nda thuc 4: ");
    inDT(dt4);


    DaThuc dt5;
    ktRong(dt5);
    nhanDT(dt1,dt2,dt5);
    printf("\nda thuc 5: ");
    inDT(dt5);
    return 0;
}