Singleton set manager in c++
0
$begingroup$
I thought a singleton set manager is better than a global set. So I wrote a singleton set manager class C.
Minimal requirement of the class C
- must have insert() to insert a new item(int)
- must have has() to check if it has the item
- should be a singleton
Questions
- I wonder this is a good singleton implementation or not.
- How can I make this code better?
Code
#include <iostream>
#include <iterator>
#include <set>
#include <vector>
#include <initializer_list>
class C {
std::set<int> s;
public:
static C &getInstance() {
static C instance;
return instance;
}
bool insert(int i) {
std::pair<std::set<int>::iterator, bool> ret = s.insert(i);
return ret.second;
}
bool has(int i) {
return s.find(i) != s.end();
}
/* dump() is not essential */
void dump() {
std::copy(s.begin(), s.end(),
std::ostream_iterator<int>(std::cout, " "));
std::cout << "n";
}
private:
C() {}
/* prevent to call C(C const &) */
C(C const &);
/* prevent to call operator=() */
void operator=(C const &);
};
void foo(std::vector<int> &v) {
C &c = C::getInstance();
for (int i = 0; i < v.size(); i++) {
c.insert(v[i]);
}
}
void bar(std::vector<int> &v) {
C &c = C::getInstance();
for (int i = 0; i < v.size(); i++) {
std::cout << v[i] << " " << (c.has(v[i]) ? "y " : "n ");
}
std::cout << "n";
}
int main() {
std::vector<int> x{1, 3, 5, 7};
std::vector<int> y{1, 4};
std::vector<int> z{3, 4, 10};
C &c = C::getInstance();
c.dump();
foo(x);
c.dump();
bar(z);
foo(y);
c.dump();
bar(z);
}
Output
dump:
dump: 1 3 5 7
3 y 4 n 10 n
dump: 1 3 4 5 7
3 y 4 y 10 n
c++ beginner singleton
asked 10 mins ago
H. JangH. Jang
675
$endgroup$
add a comment |
0
$begingroup$
I thought a singleton set manager is better than a global set. So I wrote a singleton set manager class C.
Minimal requirement of the class C
- must have insert() to insert a new item(int)
- must have has() to check if it has the item
- should be a singleton
Questions
- I wonder this is a good singleton implementation or not.
- How can I make this code better?
Code
#include <iostream>
#include <iterator>
#include <set>
#include <vector>
#include <initializer_list>
class C {
std::set<int> s;
public:
static C &getInstance() {
static C instance;
return instance;
}
bool insert(int i) {
std::pair<std::set<int>::iterator, bool> ret = s.insert(i);
return ret.second;
}
bool has(int i) {
return s.find(i) != s.end();
}
/* dump() is not essential */
void dump() {
std::copy(s.begin(), s.end(),
std::ostream_iterator<int>(std::cout, " "));
std::cout << "n";
}
private:
C() {}
/* prevent to call C(C const &) */
C(C const &);
/* prevent to call operator=() */
void operator=(C const &);
};
void foo(std::vector<int> &v) {
C &c = C::getInstance();
for (int i = 0; i < v.size(); i++) {
c.insert(v[i]);
}
}
void bar(std::vector<int> &v) {
C &c = C::getInstance();
for (int i = 0; i < v.size(); i++) {
std::cout << v[i] << " " << (c.has(v[i]) ? "y " : "n ");
}
std::cout << "n";
}
int main() {
std::vector<int> x{1, 3, 5, 7};
std::vector<int> y{1, 4};
std::vector<int> z{3, 4, 10};
C &c = C::getInstance();
c.dump();
foo(x);
c.dump();
bar(z);
foo(y);
c.dump();
bar(z);
}
Output
dump:
dump: 1 3 5 7
3 y 4 n 10 n
dump: 1 3 4 5 7
3 y 4 y 10 n
c++ beginner singleton
asked 10 mins ago
H. JangH. Jang
675
$endgroup$
add a comment |
0
0
0
$begingroup$
I thought a singleton set manager is better than a global set. So I wrote a singleton set manager class C.
Minimal requirement of the class C
- must have insert() to insert a new item(int)
- must have has() to check if it has the item
- should be a singleton
Questions
- I wonder this is a good singleton implementation or not.
- How can I make this code better?
Code
#include <iostream>
#include <iterator>
#include <set>
#include <vector>
#include <initializer_list>
class C {
std::set<int> s;
public:
static C &getInstance() {
static C instance;
return instance;
}
bool insert(int i) {
std::pair<std::set<int>::iterator, bool> ret = s.insert(i);
return ret.second;
}
bool has(int i) {
return s.find(i) != s.end();
}
/* dump() is not essential */
void dump() {
std::copy(s.begin(), s.end(),
std::ostream_iterator<int>(std::cout, " "));
std::cout << "n";
}
private:
C() {}
/* prevent to call C(C const &) */
C(C const &);
/* prevent to call operator=() */
void operator=(C const &);
};
void foo(std::vector<int> &v) {
C &c = C::getInstance();
for (int i = 0; i < v.size(); i++) {
c.insert(v[i]);
}
}
void bar(std::vector<int> &v) {
C &c = C::getInstance();
for (int i = 0; i < v.size(); i++) {
std::cout << v[i] << " " << (c.has(v[i]) ? "y " : "n ");
}
std::cout << "n";
}
int main() {
std::vector<int> x{1, 3, 5, 7};
std::vector<int> y{1, 4};
std::vector<int> z{3, 4, 10};
C &c = C::getInstance();
c.dump();
foo(x);
c.dump();
bar(z);
foo(y);
c.dump();
bar(z);
}
Output
dump:
dump: 1 3 5 7
3 y 4 n 10 n
dump: 1 3 4 5 7
3 y 4 y 10 n
c++ beginner singleton
asked 10 mins ago
H. JangH. Jang
675
$endgroup$
I thought a singleton set manager is better than a global set. So I wrote a singleton set manager class C.
Minimal requirement of the class C
- must have insert() to insert a new item(int)
- must have has() to check if it has the item
- should be a singleton
Questions
- I wonder this is a good singleton implementation or not.
- How can I make this code better?
Code
#include <iostream>
#include <iterator>
#include <set>
#include <vector>
#include <initializer_list>
class C {
std::set<int> s;
public:
static C &getInstance() {
static C instance;
return instance;
}
bool insert(int i) {
std::pair<std::set<int>::iterator, bool> ret = s.insert(i);
return ret.second;
}
bool has(int i) {
return s.find(i) != s.end();
}
/* dump() is not essential */
void dump() {
std::copy(s.begin(), s.end(),
std::ostream_iterator<int>(std::cout, " "));
std::cout << "n";
}
private:
C() {}
/* prevent to call C(C const &) */
C(C const &);
/* prevent to call operator=() */
void operator=(C const &);
};
void foo(std::vector<int> &v) {
C &c = C::getInstance();
for (int i = 0; i < v.size(); i++) {
c.insert(v[i]);
}
}
void bar(std::vector<int> &v) {
C &c = C::getInstance();
for (int i = 0; i < v.size(); i++) {
std::cout << v[i] << " " << (c.has(v[i]) ? "y " : "n ");
}
std::cout << "n";
}
int main() {
std::vector<int> x{1, 3, 5, 7};
std::vector<int> y{1, 4};
std::vector<int> z{3, 4, 10};
C &c = C::getInstance();
c.dump();
foo(x);
c.dump();
bar(z);
foo(y);
c.dump();
bar(z);
}
Output
dump:
dump: 1 3 5 7
3 y 4 n 10 n
dump: 1 3 4 5 7
3 y 4 y 10 n
c++ beginner singleton
c++ beginner singleton
asked 10 mins ago
H. JangH. Jang
675
asked 10 mins ago
H. JangH. Jang
675
asked 10 mins ago
H. JangH. Jang
675
asked 10 mins ago
H. JangH. Jang
675
asked 10 mins ago
H. JangH. Jang
675
675
add a comment |
add a comment |
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