C library function to perform sort

Question

Is there any library function available in C standard library to do sort

User · Answer

try qsort in stdlib h

User · Answer

C C   standard library  lt stdlib h gt  contains qsort function   This is not the best quick sort implementation in the world but it fast enough and VERY EASY to be used    the formal syntax of qsort  is   qsort  lt arrayname gt   lt size gt  sizeof  lt elementsize gt   compare function     The only thing that you need to implement is the compare function  which takes in two arguments of type  const void   which can be cast to appropriate data structure  and then return one of these three values    negative  if a should be before b 0  if a equal to b positive  if a should be after b   1  Comparing a list of integers   simply cast a and b to integers if x  lt  y x-y is negative  x    y  x-y   0  x  gt  y  x-y is positive x-y is a shortcut way to do it    reverse  x -  y to  y -  x for sorting in decreasing reverse order  int compare function const void  a const void  b    int  x    int    a  int  y    int    b  return  x -  y      2  Comparing a list of strings   For comparing string  you need strcmp function inside  lt string h gt  lib  strcmp will by default return -ve 0 ve appropriately    to sort in reverse order  just reverse the sign returned by strcmp   include  lt string h gt  int compare function const void  a const void  b    return  strcmp  char   a  char   b        3  Comparing floating point numbers   int compare function const void  a const void  b    double  x    double    a  double  y    double    b     return  x -  y     this is WRONG    if   x  lt   y  return -1  else if   x  gt   y  return 1  return 0      4  Comparing records based on a key   Sometimes you need to sort a more complex stuffs  such as record  Here is the simplest way to do it using qsort library   typedef struct   int key  double value    the record   int compare function const void  a const void  b    the record  x    the record    a  the record  y    the record    b  return x- gt key - y- gt key

User · Answer

There are several C sorting functions available in stdlib h  You can do man 3 qsort on a unix machine to get a listing of them but they include    heapsort quicksort mergesort

User · Answer

I think you are looking for qsort  qsort function is the implementation of quicksort algorithm found in stdlib h in C C    Here is the syntax to call qsort function  void qsort void  base  size t nmemb  size t size int   compar  const void    const void       List of arguments  base  pointer to the first element or base address of the array  nmemb  number of elements in the array  size  size in bytes of each element  compar  a function that compares two elements Here is a code example which uses qsort to sort an array   include  lt stdio h gt   include  lt stdlib h gt   int arr       33  12  6  2  76        compare function  compares two elements int compare  const void   num1  const void   num2       if   int  num1  gt    int  num2      return 1     else     return -1     int main         int i      printf  quot Before sorting the array   n quot       for  i   0   i  lt  5  i             printf  quot  d  quot   arr i               calling qsort    qsort arr  5  sizeof int   compare       printf  quot  nAfter sorting the array   n quot       for  i   0   i  lt  5  i                printf  quot  d  quot   arr i               return 0     You can type man 3 qsort in Linux Mac terminal to get a detailed info about qsort  Link to qsort man page

User · Answer

While not in the standard library exactly  https   github com swenson sort has just two header files you can include to get access to a wide range of incredibly fast sorting routings  like so     define SORT NAME int64  define SORT TYPE int64 t  define SORT CMP x  y    x  -  y    include  sort h     You now have access to int64 quick sort  int64 tim sort  etc   e g      int64 quick sort arr  128      Assumes you have some int  arr or int arr 128        This should be at least twice as fast as the standard library qsort  since it doesn t use function pointers  and has many other sorting algorithm options to choose from   It s in C89  so should work in basically every C compiler

User · Answer

For sure   qsort   is an implementation of a sort  not necessarily quicksort as its name might suggest    Try man 3 qsort or have a read at http   linux die net man 3 qsort

User · Answer

Use qsort   in  lt stdlib h gt     paxdiablo The qsort   function conforms to ISO IEC 9899 1990    ISO C90

User · Answer

qsort   is the function you re looking for  You call it with a pointer to your array of data  the number of elements in that array  the size of each element and a comparison function   It does its magic and your array is sorted in-place  An example follows    include  lt stdio h gt   include  lt stdlib h gt  int comp  const void   elem1  const void   elem2         int f      int  elem1       int s      int  elem2       if  f  gt  s  return  1      if  f  lt  s  return -1      return 0    int main int argc  char  argv           int x      4 5 2 3 1 0 9 8 6 7        qsort  x  sizeof x  sizeof  x   sizeof  x   comp        for  int i   0   i  lt  10   i            printf    d    x i         return 0

[c] C library function to perform sort

Examples related to c

Examples related to sorting