新人求解vc++书上二元重载

#include <iostream>
using namespace std;
class IntArray
{
private:
    int* pInt;
    int nCount;
public:
    IntArray(int count){
        nCout=count
        pInt=new int[nCount];
    }
    ~IntArray(){
        delete[]pInt;
        pInt=NULL;
                                            }
    }
    int operator[](int index) const{
        if(index<0 || index>=nCout)
            return 0;
        return pInt[index];
    }
    void SetAt(int index,int value){
        if(index<0 || index>=nCount)
            return;
        pInt[index]=value;
    }
    int GetLength(){
        return nCount;
    }
};
int main()
{
    IntArray arr(3);
    arr.SetAt(0,12);
    arr.SetAt(1,45);
    arr.SetAt(2,80);
    for(int i=0;i<<arr.GetLength();i++0
    {
        cout<<"第"<<i+1<<"个元素"<<arr[i]<<endl;
    }
    cout<<endl;
    return 0;
}
按书上打的二元重载 这能用于什么