c - 为什么我在二分搜索的实现中遇到段错误？

Question

我目前正在尝试通过递归实现二分搜索并创建用户输入提示。每当我输入一个数字并搜索它时，我总是会遇到段错误(核心转储)。我在 CS50 设备中编写了此代码。

#include <stdio.h>
#include <stdlib.h>
#include <cs50.h>
#include <ctype.h>
#include <string.h>


int findMidpoint(int min, int max);
int binarySearch(int key, int array[], int min, int max);


int main(int argc, string argv[])
{
    int array[] = {1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23};
    printf("Please search for a number : ");
    int key = GetInt();
    int search = binarySearch(key, &array, array[0], array[22]);
    printf("Result: %i \n", search);
}

int findMidpoint(int min, int max)
{
    int sum = min + max;
    int mid = sum/2;

    return mid;
}

int binarySearch(int key, int array[], int min, int max)
{
    if(min > max)
    {
        return -1;
    }
    else
    {
        int midpoint = findMidpoint(min, max);

        if(array[midpoint] < key)
        {
            binarySearch(key, array, midpoint+1, max);
        }

        else if(array[midpoint] > key)
        {
            binarySearch(key, array, midpoint-1, max);
        }
        else
        {
            return midpoint;
        }

    }

    return -1;
}

Answer 1

这是经过一些修改后的代码:

#include <stdio.h>
#include <stdlib.h>
#include <cs50.h>
#include <ctype.h>
#include <string.h>

int findMidpoint(int min, int max);
int binarySearch(int key, int array[], int min, int max);

int main(int argc, char** argv) {
    int array[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17,
            18, 19, 20, 21, 22, 23 };
    printf("Please search for a number : ");
    int key = GetInt();
    int search = binarySearch(key, array, 0, 22);
    printf("Result: %i \n", search);
}

int findMidpoint(int min, int max) {
    int sum = min + max;
    int mid = sum / 2;

    return mid;
}

int binarySearch(int key, int array[], int min, int max) {
    int midpoint = findMidpoint(min, max);
    if (array[midpoint] < key) {
        return binarySearch(key, array, midpoint + 1, max);
    } else if (array[midpoint] > key) {
        return binarySearch(key, array, min, midpoint - 1);
    } else {
        return array[midpoint];
    }
    return -1;
}

请注意，每次递归调用 binarySearch 时，您都需要返回结果。