set lower_boumd
时间: 2023-11-20 16:58:16 浏览: 46
set的lower_bound函数返回第一个大于等于给定值的元素的迭代器,如果不存在这样的元素,则返回set.end()。下面是一个示例代码:
```cpp
#include <iostream>
#include <set>
using namespace std;
int main() {
set<int> s;
s.insert(1);
s.insert(3);
s.insert(5);
s.insert(7);
s.insert(9);
set<int>::iterator it = s.lower_bound(6);
if (it == s.end()) {
cout << "No element greater than or equal to 6" << endl;
} else {
cout << "The first element greater than or equal to 6 is " << *it << endl;
}
it = s.lower_bound(5);
if (it == s.end()) {
cout << "No element greater than or equal to 5" << endl;
} else {
cout << "The first element greater than or equal to 5 is " << *it << endl;
}
return 0;
}
```
输出结果为:
```
The first element greater than or equal to 6 is 7
The first element greater than or equal to 5 is 5
```