How can object be allocated outside the object lifetime?
What must be an operand of operator delete?
What is the output of this program?
1.
#include
2.
#include
3.
#include
4.
using namespace std;
5.
const int bsize = 512;
6.
int *pa;
7.
bool allocate = true;
8.
void get_memory()
9.
{
10.
cerr << "free store exhausted" << endl;
11.
delete [] pa;
12.
allocate = false;
13.
}
14.
void eat_memory(int size)
15.
{
16.
int *p = new int[size];
17.
if (allocate)
18.
eat_memory(size);
19.
else
20.
cerr << "free store addr = " << p << endl;
21.
}
22.
int main()
23.
{
24.
set_new_handler(get_memory);
25.
pa = new int[bsize];
26.
cerr << "free store addr = " << pa << endl;
27.
eat_memory(bsize);
28.
return 0;
29.
}
What is the output of this program?
1.
#include
2.
#include
3.
#include
4.
using namespace std;
5.
class X;
6.
struct Node
7.
{
8.
X* data;
9.
bool filled;
10.
Node() : filled(false) { }
11.
};
12.
class X
13.
{
14.
static Node buffer[];
15.
public:
16.
int number;
17.
enum { size = 3};
18.
void* operator new(size_t sz) throw (const char*)
19.
{
20.
void* p = malloc(sz);
21.
if (sz == 0)
22.
throw "Error: malloc() failed";
23.
cout << "X :: operator new(size_t)" << endl;
24.
return p;
25.
}
26.
void *operator new(size_t sz, int location) throw (const char*)
27.
{
28.
cout << "X :: operator new(size_t, " << location << ")" << endl;
29.
void* p = 0;
30.
if (location < 0 || location >= size || buffer[location].filled == true)
31
{
32.
throw "Error: buffer location occupied";
33.
}
34.
else
35.
{
36.
p = malloc(sizeof(X));
37.
if (p == 0)
38.
throw "Error: Creating X object failed";
39.
buffer[location].filled = true;
40.
buffer[location].data = (X*) p;
41.
}
42.
return p;
43.
}
44.
static void printbuffer()
45.
{
46.
for (int i = 0; i < size; i++)
47.
{
48.
cout << buffer[i].data->number << endl;
49.
}
50.
}
51.
};
52.
Node X::buffer[size];
53.
int main()
54.
{
55.
try
56.
{
57.
X* ptr1 = new X;
58.
X* ptr2 = new(0) X;
59.
X* ptr3 = new(1) X;
60.
X* ptr4 = new(2) X;
61.
ptr2->number = 10000;
62.
ptr3->number = 10001;
63.
ptr4->number = 10002;
64.
X :: printbuffer();
65.
X* ptr5 = new(0) X;
66.
}
67.
catch (const char* message)
68.
{
69.
cout << message << endl;
70.
}
71.
}
What is the output of this program?
1.
#include
2.
#include
3.
using namespace std;
4.
class X
5.
{
6.
public:
7.
void* operator new(size_t sz) throw (const char*)
8.
{
9.
void* p = malloc(sz);
10.
if (p == 0)
11.
throw "malloc() failed";
12.
return p;
13.
}
14.
void operator delete(void* p)
15.
{
16.
cout << "X :: operator delete(void*)" << endl;
17.
free(p);
18.
}
19.
};
20.
class Y
21.
{
22.
int filler[100];
23.
public:
24.
void operator delete(void* p, size_t sz) throw (const char*)
25.
{
26.
cout << "Freeing " << sz << " bytes" << endl;
27.
free(p);
28.
};
29.
};
30.
int main()
31.
{
32.
X* ptr = new X;
33.
delete ptr;
34.
Y* yptr = new Y;
35.
delete yptr;
36.
}