bsearch | binary searching a sorted file | Learning library

Your generic is:

1. You are passing strcmp to bsearch. strcmp takes const char* arguments, bsearch epects a function with const void*.
2. You are passing strcmp to bsearch. It compares strings, not elements of fruit_shelf_t.
3. myStrCmp still compares strings, not fruit_shelf_t with key.
4. Do not cast the result of bsearch. Do not cast the function pointer to a different type.
5. for(int i; i < is not initializting i...
6. if(!buff){ checks if buff is not set. Should be if(buff){.

1. I see no reason to pass a pointer to a char *, just pass the key itself.
2. The callback from bsearch compares key with the element from the array.

how gcc is able to tell you which header file corresponds to some implicitly declared functions and not others?

Gcc has a list of symbols and headers. When the symbol is encountered and it is not defined and it is in the list, then a message is displayed with the proposed header name.

See the list at https://github.com/gcc-mirror/gcc/blob/16e2427f50c208dfe07d07f18009969502c25dc8/gcc/c-family/known-headers.cc#L157 from gcc sources.

bsearch is not in the list, so the hint is not displayed. I like the hints, it would be nice for me to include all the symbols from C standard, including bsearch. It would also be a speedup if the list would be sorted and would use bsearch. You can contribute to gcc or donate to gcc and write about it to gcc mailing list.

For a given value of el, match_idx will equal a non-negative integer (an index of arr) if there is an index el2 of arr such that arr[el] + arr[el2] == target, else match_idx will equal nil, so you have to make sure match_id is not nil before checking match_idx != i.

Let's see if we can make the method more efficient, considering that the time complexity of sorting is O(nlog(n)), where n is the size of the array.

Within the function you need to find each element in the passed array. However the type of the array is unknown. You only know the size of each element of the array and the starting address of the array that is passed through the parameter base0. of the type const void *..

To access an element of the array you need to use the pointer arithmetic. But the type void is incomplete type. Its size is unknown/ So you may not use the pointer of the type (const) void *` in expressions with the pointer arithmetic.

Thus this declaration

It's not a matter of programming language but of algorithm. First, you need a quick way to look up the genres for each song. To do that, you can first sort the genres by that long key, then do a binary search using the key.

Your structs should be as follows:

As noted in the comments, the primary problem is that you misassign the tokens without using strcpy(). As wildplasser noted in a comment, it is simpler to use the POSIX strdup() function (which is not yet a part of standard C, though that might change in C2x).

The secondary problem is that word includes the newline and the tokens never include the newline. You need to remove that.

This code makes those changes and adds a function to dump the array of strings.

The pointers passed to compare are pointers to char*, so you have to dereference them to get char* that point at strings to be compared.

Running under gdb, after the fault, doing a tb command to get a stack traceback, we see: