Something

#include <stdio.h> 
   #include <string.h> 
 
   #define MAXLINES 5000     /* max #lines to be sorted */ 
   char *lineptr[MAXLINES];  /* pointers to text lines */ 
 
   int readlines(char *lineptr[], int nlines); 
   void writelines(char *lineptr[], int nlines); 
 
   void qsort(void *lineptr[], int left, int right, 
              int (*comp)(void *, void *)); 
   int numcmp(char *, char *); 
 
   /* sort input lines */ 
   main(int argc, char *argv[]) 
   { 
       int nlines;        /* number of input lines read */ 
       int numeric = 0;   /* 1 if numeric sort */ 
 
       if (argc > 1 && strcmp(argv[1], "-n") == 0) 
           numeric = 1; 
       if ((nlines = readlines(lineptr, MAXLINES)) >= 0) { 
           qsort((void**) lineptr, 0, nlines-1, 
             (int (*)(void*,void*))(numeric ? numcmp : strcmp)); 
           writelines(lineptr, nlines); 
         return 0; 
     } else { 
         printf("input too big to sort\n"); 
         return 1; 
     }