Set Basics in C++

1#include <iostream>
2#include <set>
3using namespace std;
4
5int main() {
6    // Create set
7    set<int> numbers;
8    
9    // Insert elements
10    numbers.insert(5);
11    numbers.insert(2);
12    numbers.insert(8);
13    numbers.insert(1);
14    numbers.insert(5);  // Duplicate, will be ignored
15    numbers.insert(3);
16    
17    // Display set
18    cout << "Set elements (sorted and unique): ";
19    for (int num : numbers) {
20        cout << num << " ";
21    }
22    cout << endl;
23    
24    // Check if element exists
25    if (numbers.find(5) != numbers.end()) {
26        cout << "Element 5 found in set" << endl;
27    }
28    
29    // Count occurrences (0 or 1 for set)
30    cout << "Count of 5: " << numbers.count(5) << endl;
31    cout << "Count of 10: " << numbers.count(10) << endl;
32    
33    // Size
34    cout << "Set size: " << numbers.size() << endl;
35    
36    // Erase element
37    numbers.erase(5);
38    cout << "\nAfter erasing 5: ";
39    for (int num : numbers) {
40        cout << num << " ";
41    }
42    cout << endl;
43    
44    // Lower and upper bound
45    set<int> s = {1, 2, 3, 5, 7, 9};
46    auto it_low = s.lower_bound(4);  // First element >= 4
47    auto it_up = s.upper_bound(6);   // First element > 6
48    
49    cout << "\nLower bound of 4: " << *it_low << endl;
50    cout << "Upper bound of 6: " << *it_up << endl;
51    
52    return 0;
53}