Mega Code Archive
Demonstrating STL vector constructors with a user-defined type and showing copying explicitly
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#include <iostream>
#include <cassert>
#include <vector>
using namespace std;
class MyClass {
public:
unsigned long id;
unsigned long generation;
static unsigned long total_copies;
MyClass() : id(0), generation(0) { }
MyClass(unsigned long n) : id(n), generation(0) { }
MyClass(const MyClass& z) : id(z.id), generation(z.generation + 1) {
++total_copies;
}
};
bool operator==(const MyClass& x, const MyClass& y)
{
return x.id == y.id;
}
bool operator!=(const MyClass& x, const MyClass& y)
{
return x.id != y.id;
}
unsigned long MyClass::total_copies = 0;
int main()
{
vector<MyClass> vector1, vector2(3);
assert (vector1.size() == 0);
assert (vector2.size() == 3);
assert (vector2[0] == MyClass() && vector2[1] == MyClass() &&
vector2[2] == MyClass());
for (int i = 0; i != 3; ++i)
cout << "vector2[" << i << "].generation: " << vector2[i].generation << endl;
cout << "Total copies: " << MyClass::total_copies << endl;
return 0;
}
vector2[0].generation: 1
vector2[1].generation: 1
vector2[2].generation: 1
Total copies: 3
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