Hello, I am working on a project for school. I need to search through an array of strings in order to be able to delete a particular entry in the array. However my binary search function keeps returning -1 (not found). I can't figure out why.
I can print the array, quick sort the array, add to it, but my search function is failing, which means that I can't delete an entry. I sort the array before I search it.
Could anyone please help my understand why it returns -1 no matter what?
Thank you for your help.
#define LIMIT 50;
StudentRecord students[LIMIT]; // there are 35 entries in the array, but the
//LIMIT is set to 50
//call to the function
cout << "Enter a name to search for: "; // I only need to search my the name
index = biSearch(students, 0, LIMIT, searchTerm); // there are about 15 //empty entries in the array. I tried to only search those records that had data //in them, but it still failed.
// biSearch function definition
int biSearch(StudentRecord students[LIMIT], int start, int finish, string searchTerm)
int mid = (start+finish)/2;
if (finish-start+1 > 0)
if (students[mid].name == searchTerm)
elseif (searchTerm < students[mid].name)
return biSearch(students, start, mid-1, searchTerm);
elsereturn biSearch(students, mid+1, finish, searchTerm);
My guess is that you don't want the undefined behavior caused by flushing an input stream on line 15, so I would suggest removing that line. You may want to substitute: cin >> ws; to consume any leading whitespace before using getline.
Otherwise the code looks reasonable, assuming case matches and the array has been correctly populated and sorted. Of course, those are big assumptions.
I removed the line 15 and used cin >> searchTerm, but I am still getting -1 as a response.
I am starting to think that the search is okay, but something else is wrong. I will double check the sort function, but it looks okay, especially since the list is sorted property when I print it out. I really don't understand what is going on. I will post an answer if I figure it out.
It didn't work because when I read the names from the file into the array, the program read the mane with a space after it, so even though the search found a match, it wasn't exact match, because it had a space in there.
The problem is that I thought about it and told it to dump the space at the end using the string.erase function. It just didn't do it.
Also, when I was debugging in Visual Studio, debugger was telling me the the value in the search term was without a space, which was incorrect.
So I got lost in this problem for a while, but I got it now.