Sorting and Searching: std::sort, std::stable_sort, std::binary_search

Intermediate13 min read•Updated: 2026-10-22

⚡ Sorting and Searching: std::sort and std::binary_search

Introduction

C++ provides high-performance algorithms in <algorithm>. Under the hood, std::sort implements Introsort (a hybrid of Quicksort, Heapsort, and Insertion Sort) running in optimal O(N log N) time.

📊 Sorting Vectors

1#include <iostream>
2#include <vector>
3#include <algorithm>
4 
5int main() {
6    std::vector<int> scores = {78, 92, 45, 88, 63, 99, 52};
7 
8    // 1. Ascending Sort:
9    std::sort(scores.begin(), scores.end());
10 
11    std::cout << "Sorted Ascending: ";
12    for (int s : scores) std::cout << s << " ";
13    std::cout << "\n";
14 
15    // 2. Descending Sort using std::greater<int>():
16    std::sort(scores.begin(), scores.end(), std::greater<int>());
17 
18    std::cout << "Sorted Descending: ";
19    for (int s : scores) std::cout << s << " ";
20    std::cout << "\n";
21 
22    return 0;
23}

🔎 Binary Search in O(log N) Time

Prerequisite: Data must be sorted before calling binary search algorithms!

1#include <iostream>
2#include <vector>
3#include <algorithm>
4 
5int main() {
6    std::vector<int> rollNumbers = {101, 105, 108, 114, 120, 135};
7 
8    int target = 114;
9 
10    // std::binary_search returns bool
11    if (std::binary_search(rollNumbers.begin(), rollNumbers.end(), target)) {
12        std::cout << "Roll #" << target << " is enrolled in this batch!\n";
13    }
14 
15    // std::lower_bound returns an iterator to the first element >= target
16    auto it = std::lower_bound(rollNumbers.begin(), rollNumbers.end(), target);
17    if (it != rollNumbers.end()) {
18        std::cout << "Found at index: " << std::distance(rollNumbers.begin(), it) << "\n";
19    }
20 
21    return 0;
22}

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Transforming and Accumulating: std::transform, std::accumulate, std::count_if

Continue learning with hands-on practice, examples, and exercises in the upcoming topic.

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Iterator Types: begin(), end(), rbegin(), rend(), cbegin()	Transforming and Accumulating: std::transform, std::accumulate, std::count_if

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Transforming and Accumulating: std::transform, std::accumulate, std::count_if

Sorting and Searching: std::sort, std::stable_sort, std::binary_search

Intermediate13 min read•Updated: 2026-10-22

Study Materials

⚡ Sorting and Searching: std::sort and std::binary_search

Introduction

📊 Sorting Vectors

1#include <iostream>
2#include <vector>
3#include <algorithm>
4 
5int main() {
6    std::vector<int> scores = {78, 92, 45, 88, 63, 99, 52};
7 
8    // 1. Ascending Sort:
9    std::sort(scores.begin(), scores.end());
10 
11    std::cout << "Sorted Ascending: ";
12    for (int s : scores) std::cout << s << " ";
13    std::cout << "\n";
14 
15    // 2. Descending Sort using std::greater<int>():
16    std::sort(scores.begin(), scores.end(), std::greater<int>());
17 
18    std::cout << "Sorted Descending: ";
19    for (int s : scores) std::cout << s << " ";
20    std::cout << "\n";
21 
22    return 0;
23}

🔎 Binary Search in O(log N) Time

Prerequisite: Data must be sorted before calling binary search algorithms!

1#include <iostream>
2#include <vector>
3#include <algorithm>
4 
5int main() {
6    std::vector<int> rollNumbers = {101, 105, 108, 114, 120, 135};
7 
8    int target = 114;
9 
10    // std::binary_search returns bool
11    if (std::binary_search(rollNumbers.begin(), rollNumbers.end(), target)) {
12        std::cout << "Roll #" << target << " is enrolled in this batch!\n";
13    }
14 
15    // std::lower_bound returns an iterator to the first element >= target
16    auto it = std::lower_bound(rollNumbers.begin(), rollNumbers.end(), target);
17    if (it != rollNumbers.end()) {
18        std::cout << "Found at index: " << std::distance(rollNumbers.begin(), it) << "\n";
19    }
20 
21    return 0;
22}

Next Lesson

Transforming and Accumulating: std::transform, std::accumulate, std::count_if

Continue learning with hands-on practice, examples, and exercises in the upcoming topic.

Related Lessons

Previous Lesson	Next Lesson
Iterator Types: begin(), end(), rbegin(), rend(), cbegin()	Transforming and Accumulating: std::transform, std::accumulate, std::count_if

Practice Quiz

Test your understanding of this lesson with 1 questions. Each question has one correct answer.

Previous Next