Difference Between Stdsetupper Bound And Stdupper Bound In C++

In this tutorial, we are going to explore the variance between the std::upperbound and std::set::upperbound functions in C++. Prior to delving into their distinctions, it is essential to understand the std::upperbound and std::set::upperbound functions along with their syntax and usage examples.

What is the std::set::upper_bound?

It is a member method of the std::set container class. It provides an iterator that points to the initial element in the set exceeding a given value.

Syntax:

It has the following syntax:

std::set<T>::iterator std::set<T>::upper_bound(const T& value);

where "T" represents the element contained within the set data structure

"value" is the value that is searched for.

Example:

Let's consider a scenario to illustrate the functionality of the std::set::upper_bound method in C++.

#include <iostream>
#include <set>
int findNextAvailableSlot(const std::set<int>& bookedSlots, int proposedStartTime) {
    auto it = bookedSlots.upper_bound(proposedStartTime);
    if (it != bookedSlots.end()) {
        return *it;
    } else {
        return -1;
    }
}

int main() {
    std::set<int> bookedSlots = {1, 3, 5, 7, 9};
    int proposedStartTime = 5;

    int nextAvailableSlot = findNextAvailableSlot(bookedSlots, proposedStartTime);
    if (nextAvailableSlot != -1) {
        std::cout << "Next available slot starts at: " << nextAvailableSlot << std::endl;
    } else {
        std::cout << "All slots are booked." << std::endl;
    }
    return 0;
}

Output:

Explanation:

There exist two functions within the aforementioned program. The variables utilized in the findNextAvailableSlot function are bookedSlots, denoting the reserved time slots, and proposedStartTime indicating the meeting's starting time. This particular function identifies the initial booked slot in bookedSlots that commences post the proposedStartTime. In case a suitable slot is identified, it provides the starting time; if not, it returns -1.

The primary function consists of three variables: reservedSlots, indicating the time slots already booked; suggestedStartTime, denoting the starting time of the upcoming meeting; and followingVacantSlot, designated for storing the function's output. Its purpose is to generate a collection of reserved time intervals. Following the evaluation, it will display a relevant message depending on the slot's availability.

What is the set::upper_bound?

It is a common algorithm within the C++ standard template library. The <algorithm> header is required to incorporate this functionality into our program. The algorithm is designed to provide an iterator that points to the initial element within a range that surpasses a specified value.

Syntax:

It has the following syntax:

template<class ForwardIt, class T>
ForwardIt std::upper_bound(ForwardIt first, ForwardIt last, const T& value);

"ForwardIt" is a iterator type.

The "first" and "last" iterators establish the range within which the search is conducted.

"value" is the value to search for.

Example:

Let's consider a C++ code example to showcase the functionality of the std::upper_bound method:

#include <iostream>
#include <set>
#include <algorithm>
int findNextAvailableSlot(const std::set<int>& bookedSlots, int proposedStartTime) {
    auto it = std::upper_bound(bookedSlots.begin(), bookedSlots.end(), proposedStartTime);
    if (it != bookedSlots.end()) {
        return *it;
    } else {
        return -1;
    }
}

int main() {
    std::set<int> bookedSlots = {1, 3, 5, 7, 9};
    int proposedStartTime = 5;
    int nextAvailableSlot = findNextAvailableSlot(bookedSlots, proposedStartTime);
    if (nextAvailableSlot != -1) {
        std::cout << "Next available slot starts at: " << nextAvailableSlot << std::endl;
    } else {
        std::cout << "All slots are booked." << std::endl;
    }
    return 0;
}

Output:

Explanation:

This software provides identical functionality to the prior version, although the approach taken here is distinct. In this case, the findNextAvailableSlot function leverages std::upper_bound alongside an iterator derived from bookedSlots.begin and bookedSlots.end. The remaining program logic mirrors that of the earlier version.

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

There exist various distinctions between the std::upperbound function and the std::set::upperbound method in the C++ programming language. A few key variances between these functions include: