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#include <iostream>
char const *s = R"(
Lorem ipsum dolor sit amet.
It was the age of reason.
It was the age of foolishness.
do {
class x;
} while (0.1238712e+12 != CHAR_MAX);
)";
using std::cout;
template<typename T>
class Option {
public:
Option<T>() {
exists = false;
}
Option<T>(T const &t) {
set(t);
}
void set(T const &t) {
exists = true;
x = t;
}
void clear() {
exists = false;
}
T *get() {
if (exists)
return &x;
else
return nullptr;
}
T const *get() const {
if (exists)
return &x;
else
return nullptr;
}
private:
bool exists;
T x;
};
template<typename T>
void print_option(Option<T> const &o) {
T const *ptr = o.get();
if (ptr)
cout << *ptr << "\n";
else
cout << "None\n";
}
int main() {
Option<int> o(7);
print_option(o);
o.clear();
print_option(o);
o.set(133);
print_option(o);
return 0;
}
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