c++error, 求大神看一下哪里有问题

没有compile time error, 不知道哪里出了问题

#include
#include
using namespace std;

class HW1
{
public:
char *word;
HW1() { }
~HW1() {
delete [] word;
}
};

void foo(HW1 a)
{
//some operation here
}

int main()
{
HW1 a;
a.word = new char[80];
strcpy(a.word, "abc");
foo(a);
return 0;
}

#include <cstring> 
#include <iostream>
using namespace std;
class HW1
{
public:
char *word;
HW1() { }
~HW1() {
delete [] word;
}
};
void foo(HW1& a) //加上
{
//some operation here
}
int main()
{
HW1 a;
a.word = new char[80];
strcpy(a.word, "abc");
foo(a);
return 0;
}

否则会导致拷贝了一个对象a，作为参数，指向相同的地址，两个对象调用delete导致重复释放