请指导一下这个程序的错误之处，我思索半天感觉那个指针好像运用有问题，就是不知道问题出在何处，还请大家帮忙看看啊

#include<iostream>
using namespace std;
int main()
{
    int *p,i,num,positive=0,negative=0;
    int p=new int[20];
    if (!p)
    {
        cout<<"number error.\n";
        return 1;
    }
    do{
        cin>>num;
    }while(num>20||num<1);
    for(i=0;i<num;i++)
    {
        cin>>*(p+i);
        if (*(p+i)>0)
            positive++;
        if (*(p+i)<0)
            negative++;
    }
    delete []p;
    cout<<"There are "<<num<<" figures,\n";
    cout<<positive<<" of them are positive numbers,\n";
    cout<<negative<<" of them are negatives.\n";
    return 0;
    }

[ 本帖最后由 随着心飞翔 于 2013-3-10 15:25 编辑 ]