lesson8.h

#ifndef lesson8_h
#define lesson8_h

#include <iostream>
using namespace std;
#define unlong unsigned long
#define unint unsigned int  
class leftover
{
public:
    unlong left (unlong num,unint ct);   
    char *left (const char *str,int n);
};
#endif

lesson8.cpp
#ifndef lesson8_cpp
#define lesson8_cpp

#include "lesson8.h"
unlong leftover::left (unlong num,unint ct)
{
    unint digits =1;
    unlong n =num;
    if(ct==0 || num==0)
    {
        return 0;
    }
    while(n/=10)
    {
        digits++;
    }
    if(digits>ct)
    {
        ct=digits-ct;
        while(ct--)
        {
            num /=10;
        }
        return num;
    }
    else
    {
        return num;
    }
}

char leftover::*left (const char *str,int n)
{
    if(n<0)
    {
        n=0;
    }
    char *p=new char[n+1];
    int i;
    for (i=0;i<n&&str[i];i++)
    {
        p[i]=str[i];
    }
    while(i<=n)
    {
        p[i++]='\0';
    }
    return p;
}
#endif

my_lesson8.cpp

#ifndef my_lesson8_cpp
#define my_lesson8_cpp

#include "lesson8.h"
leftover MoveLeft;
int main()
{
    char *trip =" hawaii!! ";
    unlong n = 12345678;
    int i;
    char *temp;
    for(i=1;i<10;i++)
    {
        cout<<MoveLeft.left(n,i)<<endl;
        temp=MoveLeft.left(trip,i);
        cout<<temp<<endl;
        delete []temp;
    }
    return 0;
}
#endif

错误信息
--------------------Configuration: lesson8 - Win32 Debug--------------------
Compiling...
lesson8.cpp
e:\c#\c++ project\lesson8\lesson8.cpp(65) : error C2440: 'return' : cannot convert from 'char *' to 'char leftover::*'
        There is no context in which this conversion is possible
Error executing cl.exe.

lesson8.exe - 1 error(s), 0 warning(s)

char leftover::*left (const char *str,int n)
改为：char* leftover::left (const char *str,int n)

2楼正解！！