#include<iostream>
#include<string>
#include"playpen.h"
using namespace std;

int getint( istream&source ){
int temp;
source>>temp;
if(source.fail() ){
source.clear();
cerr<<"corrupted data stream accessed in getint.\n";
throw fgw::problem("corrupted data stream.");
}
else return temp;
}
这个程序运行不了，出现以下提示？
main.c:undefined reference to 'WinMain@16'
请各位指点啊