The function bsearch () in C

The function bsearch () in C

Void function * bsearch (const void * key, const void * base, nitems, size, int (* compar) (const void *, const void *)) looks for an array of nitems objects, its original member is point to by base , for a member that connects the object pointed to by the key . The size of each array element is determined by size .

The contents of the array should be in ascending order corresponding to the comparison function referenced by compar.

Declare the function bsearch () in C

Below is the declaration for bsearch () in C:

 void * bsearch ( const void * key , const void * base , size_t nitems , size_t size , int (* compar )( const void *, const void *)) 

Parameters

key : This is the pointer to an object that acts as a key to search, is cast as a void *.

base : This is the pointer to the first object of the array, where the search is performed, cast in the form of a void *.

nitems : This is the number of elements in the array pointed to by the base.

size : This is the size (byte value) of each element in the array.

compare : This is a function to compare two elements.

Returns the value

This function returns a pointer to an entry in the array that connects to the search key. If the key is not found, the function returns a NULL pointer.

For example

The following C program illustrates the usage of bsearch () in C:

 #include #include int cmpfunc ( const void * a , const void * b ) { return ( *( int *) a - *( int *) b ); } int values [] = { 5 , 20 , 29 , 32 , 63 }; int main () { int * item ; int key = 32 ; /* su dung ham bsearch() de tim gia tri 32 trong mang */ item = ( int *) bsearch (& key , values , 5 , sizeof ( int ), cmpfunc ); if ( item != NULL ) { printf ( "Da tim thay phan tu co gia tri = %dn" , * item ); } else { printf ( "Khong tim thay phan tu co gia tri = %dn" , * item ); } return ( 0 ); } 

Compiling and running the above C program will result:

According to Tutorialspoint

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