C++ map lower_bound() Function
Example
Find the first element with a key that is equal to or greater than "Bo":
map<string, int> people = {{"John", 32}, {"Adele", 45}, {"Bo", 29}};
auto it = people.lower_bound("Bo");
cout << it->first << " is: " << it->second;Definition and Usage
The lower_bound() function returns an iterator (a pointer-like object that points to an element) to the first element with a key that is equal to or greater than the given key.
For string keys, greater means later in alphabetical order. If there is no such element, it returns end().
The lower_bound function is defined in the <map> header file.
Tip: Use upper_bound() to find the first element with a key that is greater than (not equal to) the given key.
Syntax
map.lower_bound(keyType key)keyType is the type of the keys in the map, like string in the example.
Parameter Values
| Parameter | Description |
|---|---|
| key | Required. The key to compare with. |
Technical Details
| Returns: | An iterator pointing to the first element with a key that is equal to or greater than key. If there is no such element, it returns map.end(). |
|---|
Related Pages
Read more about maps in our Maps Tutorial.
