// qsort of an array of strings
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
#define numofstr 50
#define strleng 101
 
int compare(const void *,const void *);
 
int main()
{
    FILE *a, *b;
    char s[100] = { '\0' };   // preload temp string array with '\0'
    int array_size;
    int i = 0;
    char starr[numofstr][strleng] = { '\0' };  // dito
 
    // open text file, one data item per line
    a = fopen("non_sorted.txt", "r");
 
    while( 1 )
    {
        if (! fgets( s, 100, a ))
            break ;
 
        // remove trailing newline char
        if(s[strlen(s) - 1] == '\n')
            s[strlen(s) - 1] = '\0';
 
        strcpy(starr[i], s) ;
        printf("%d --> %s\n", i, starr[i]);  // test print
        i++;
    }
    // set true array size
    array_size = i;
 
    qsort(starr, array_size, strleng, compare);
 
    printf("----------- sorted ----------------\n");  // for test print
 
    // open text file to write to
    b = fopen("sorted.txt", "w");
 
    for(i = 0; i < array_size; i++)
    {
        // might add a space after string since ...\n does odd things in Pelles C!
        fprintf(b, "%s\n", starr[i]);
        printf("%d --> %s\n", i, starr[i]);  // test print
    }
 
    getchar();  // wait
    return 0 ;
}
 
int compare(const void* a, const void* b)
{
   char* arg1 = (char*) a;
   char* arg2 = (char*) b;
   // use stricmp() for case insensitive compare
   return strcmp(arg1, arg2);
}

# read a list of strings from a file, sort and write back out
# language: Python
 
# load the data lines
fin = open("non_sorted.txt", "r")
data_list = fin.readlines()
fin.close()
 
# show raw lines
for names in data_list:
    print names,
 
# inplace sort, case insensitive, much faster than qsort
data_list.sort(key=str.lower)
 
print "----------- sorted ----------------"
 
# show sorted lines
for names in data_list:
    print names,
 
# write sorted data lines back out
fout = open("sorted.txt", "w")
fout.writelines(data_list)
fout.close()