C++ 程序：二分搜索算法

原文：https://www.studytonight.com/cpp-programs/cpp-program-for-binary-search-algorithm

大家好！

在本教程中，我们将学习如何用 C++ 编程语言实现二分搜索算法。

为了详细了解二分搜索的概念，我们将推荐您访问https://www . study south . com/data-structures/binary-search-algorithm，我们已经在这里详细解释了这些概念。

为了更好地理解，请参考下面给出的评论良好的 CPP 代码。

代号:

#include <iostream>
#include <vector>
using namespace std;

//Program to return the index of b in the vector a
int BS(int a[], int l, int h, int b)
{
    int res = -1;
    while (l <= h)
    {
        int m = (l + h) / 2;

        if (a[m] == b)
        {
            return m;
        }
        else if (a[m] > b)
        {
            h = m - 1;
        }
        else
        {
            l = m + 1;
        }
    }

    return -1;
}

int main()
{
    cout << "\n\nWelcome to Studytonight :-)\n\n\n";
    cout << " =====  Program to demonstrate the Binary Search Algorithm, in CPP  ===== \n\n";

    int i, n;
    int a[] = {2, 3, 5, 8, 9, 10};

    n = sizeof(a) / sizeof(a[0]);

    cout << "\n\nThe elements of the input sorted array are :\n\n";

    for (i = 0; i < n; i++)
    {
        cout << a[i] << "  ";
    }

    int k1 = 8; //the element to find the index of

    //Calling BS() method to return the index of the element k1 if present, else -1.
    int f1 = BS(a, 0, n - 1, k1);

    if (f1 == -1)
    {
        cout << "\n\nThe element " << k1 << " is not present in the given array. ";
    }
    else
    {
        cout << "\n\nThe index of the element " << k1 << " (starting from 0) is: " << f1;
    }

    int k2 = 4; //the element to find the index of

    //Calling BS() method to return the index of the element k2 if present, else -1.
    int f2 = BS(a, 0, n - 1, k2);

    if (f2 == -1)
    {
        cout << "\n\nThe element " << k2 << " is not present in the given array. ";
    }
    else
    {
        cout << "\n\nThe index of the element " << k2 << " (starting from 0) is: " << f2;
    }

    cout << "\n\n\n";

    return 0;
}

输出:

我们希望这篇文章能帮助你更好地理解二分搜索算法的概念及其在 CPP 中的实现。如有任何疑问，请随时通过下面的评论区联系我们。

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