Search not working need some advice - c

Question

Working on a binary search. The code below should explain what I'm trying to do. The user inputs a word and then a binary search is implemented to search a wordlist. Problem is the binary search. It's running but it's not finding the word in the wordlist even though I know its there. I know the code could be better but it should work. Anyone shed any light?
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
char dictionary[400000][45];
int main(void)
{
FILE infile;
int i=0;
int num;
int index;
char buffer[45];
char userword[45];
fp1 = fopen("C:/Users/Aaron/ProgrammingAssignment/dictionary.txt","rb");
if (fp1 == NULL)
{
printf("The dictionary file did not open\n");
exit(0);
}
else
{
printf("Dictionary file is open\n");
}
while(fgets(buffer,45, fp1)!=NULL)
{
strcpy(wordlist[i],buffer);
//printf("Line %d: %s",i,wordlist[i]);
i++;
}
printf("Your wordlist is now in the dictionary array");
do
{
//fscanf(fp2,"%s", userword);
printf("Enter a word to be spell checked: ");
fgets(userword, 43, stdin);
//and do a binary search
index = BinarySearch(userword,0,i);
if(index > -1)
printf("%s was found in the wordlist", userword);
else
printf("%s was not found in the dictionary", wordcheck);
}
while(wordlist != NULL);
if(index>-1) //The word was found
{
printf("That is correctly spelled\n");
}
else
{
printf("That word is spelt wrong\n");
}
return 0;
}
int BinarySearch(const char userword[],int left,int right)
{ int high = 400000;
int low = 0;
int target;
int count = 0;
while (high >= low)
{ target = low + ((high - low) / 2);
// show tries for demonstration only
printf("%d, ",target);
if (strcmp(userword, wordlist[target]) < 0)
high = target -1;
else if (strcmp(userword, wordlist[target]) > 0)
low = target + 1;
else
return target;
}
return -1;
}

Answer 1

Your binary search function is ignoring the values left and right that are passed in.
It shouldn't.
It should probably start:
int BinarySearch(const char userword[], int left, int right)
{
int high = right;
int low = left;
You should close the dictionary after you finish reading it.
You need to consider whether right is the index of the last valid element or 'one after the index of the last element'. This might mean you need to pass i - 1 in the call to the function.
You should consider calling strcmp() once and capturing its return value; it is relatively expensive:
int rc = strcmp(userword, wordlist[target]);
if (rc == 0)
return target;
else if (rc < 0)
high = target - 1;
else
low = target - 1;