[英]Segmentation fault in Binary Search in C
我正在嘗試編寫一個程序來掃描一個輸入文件,該文件包含數組中字母的數量,字母的排序列表,要搜索的字母數量,要搜索的字母列表。 它以示例文件中顯示的格式顯示搜索結果。
我在運行時收到分段錯誤錯誤消息,並包含下面包含的代碼。 現在,在此帖子因未包含正確數量的代碼而獲得負面反饋之前,我真的不知道該分段錯誤的錯誤所在。 我在Pastebin上包含了相關文件:
#include <stdio.h>
#include <stdlib.h>
#include "Proto.h"
int main()
{
/* Accepts number of elements from user */
scanf("%d", &elements);
/* Creates dynamic array */
array = (char *) calloc(elements, sizeof(char));
/* Copies sorted values to the dynamic array */
for(i = 0; i < elements; i++)
{
scanf("%s", &array[i]);
}
/* Accepts number of elements to search */
scanf("%d", &search);
/* Searches for elements in sorted array one at a time */
for(i = 1; i <= search; i++)
{
/* Accepts value to search */
scanf("%s", &value);
/* Resets counter to 0 */
count = 0;
/* Finds location of element in the sorted list using binary search */
location = binarySearch(array, value, 0, (elements-1));
/* Checks if element is present in the sorted list */
if (location == -1)
{
printf("%4s not found!\n", value);
}
else
{
printf("%4s found at %4d iteration during iteration %4d\n", value, location, count);
}
}
free(array);
}
#include <stdio.h>
#include "Proto.h"
int binarySearch(char * nums, char svalue, int start, int end)
{
middle = (start + end) / 2;
/* Target found */
if (nums[middle] == svalue)
{
return middle;
}
/* Target not in list */
else if( start == end )
{
return -1;
}
/* Search to the left */
else if( nums[middle] > svalue )
{
count++;
return binarySearch( nums, svalue, start, (middle-1) );
}
/* Search to the right */
else if( nums[middle] < svalue )
{
count++;
return binarySearch( nums, svalue, (middle+1), end );
}
}
#ifndef _PROTO_H
#define _PROTO_H
char * array;
int elements, search, location, count, middle, i;
char value;
int binarySearch(char *, char, int, int);
#endif
Sample Input file:
6
a d n o x y
3
n x z
Sample Output file:
n found at 2 during iteration 0.
x found at 4 during iteration 1.
z not found!
我沒有檢查整個代碼,但在main.c
看到此錯誤
您的代碼
/* Creates dynamic array */
array = (char *) calloc(elements, sizeof(char));
/* Copies sorted values to the dynamic array */
for(i = 0; i < elements; i++)
{
scanf("%s", &array[i]);
}
是錯的。 你的array
應該是雙指針char **array
/* Creates dynamic array */
array = calloc(elements, sizeof(char*));
/* Copies sorted values to the dynamic array */
for(i = 0; i < elements; i++)
{
scanf("%ms", &array[i]);
}
嘗試對代碼進行划分,找出造成問題的部分,並以一小部分代碼獲得收益,這將有助於找出解決方案
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