The qsort () function in C

The qsort () function in C

Void qsort function (void * base, so-phan-tu, kich-co, int (* compar) (const void *, const void *)) arranges an array.

Qsort () function stands for Quick Sort, written based on Quick Sort algorithm.

Declaring the function qsort () in C

Below is the declaration for qsort () in C:

 void  qsort ( void * base ,  so - phan - tu ,  kich - co , int (* compar )( const void *, const void *)) 

Parameters

base : This is the pointer to the first element of the array to be sorted.

so-phan-tu : This is the number of elements in the array pointed by the base pointer.

kich-co : This is the size (in bytes) of each element in the array.

compar : The function compares two elements.

Returns the value

This function does not return any values.

For example

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

 #include #include int  values [] = { 88 , 56 , 100 , 2 , 25 }; int  cmpfunc  ( const void *  a , const void *  b ) { return ( *( int *) a  - *( int *) b  ); } int  main () { int  n ;  printf ( "Truoc khi sap xep, list co dang: n" ); for (  n  = 0 ;  n  < 5 ;  n ++ ) {  printf ( "%d " ,  values [ n ]); }  qsort ( values , 5 , sizeof ( int ),  cmpfunc );  printf ( "nSau khi sap xep, list co dang: n" ); for (  n  = 0 ;  n  < 5 ;  n ++ ) {  printf ( "%d " ,  values [ n ]); } return ( 0 ); } 

Compiling and running the above C program will result:

According to Tutorialspoint

Previous lesson: Function bsearch () in C

Next lesson: Function abs () in C