Difference between std::set::upper_bound and std::upper_bound in C++

In this article, we will discuss the difference between the std::upper_bound and std::set::upper_bound methods in C++. But before discussing their differences, we must know about std::upper_bound and std::set::upper_bound methods with their syntax and examples.

What is the std::set::upper_bound?

It is a member function of the std::set container class. It returns an iterator pointing to the first element in the set that is greater than a specified value.

Syntax:

It has the following syntax:

where "T" is the element stored in the set container

"value" is the value that is searched for.

Example:

Let us take an example to demonstrate the std::set::upper_bound() function in C++.

Output:

Explanation:

There are two functions in the above program. The variables in the findNextAvailableSlot function are bookedSlots, which represent the booked time slots, and proposedStartTime will mean the start time of a meeting. This function uses the first booked slot in bookedSlots that starts after the proposedStartTime. If a slot is found, it returns the start time; otherwise, it returns -1.

The main function has three variables: bookedSlots, which represent the already booked time slots; proposedStartTime, which means the start time of the new meeting; and nextAvailableSlot, which is used to store the result of the function. This function will create a set of booked times. It checks the result and prints the appropriate message based on whether a slot is available.

What is the set::upper_bound?

It is a generic algorithm in the C++ standard template library. We use the <algorithm> header to include this in our program. It will return an iterator pointing to the first element in the range greater than a specified value.

Syntax:

It has the following syntax:

"ForwardIt" is a iterator type.

"first" and "last" iterators define the range to search in.

"value" is the value to search for.

Example:

Let us take a C++ program to demonstrate the std::upper_bound function:

Output:

Explanation:

This program has the same functionality as the previous program, but the implementation is different here. The findNextAvailableSlot function uses the std::upper_bound with an iterator obtained from bookedSlots.begin() and bookedSlots.end(). The rest of the program logic is the same as the previous program.

Main difference between the std::upper_bound and std::set::upper_bound:

There are several differences between the std::upper_bound and the std::set::upper_bound methods in C++. Some main differences between these methods are as follows: