experimento con quicksort, C (gcc)

Language: Layout:

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>

typedef struct
{
    char mail[321];
    char domain[256];    
}users;

typedef struct
{
    char dominio[256];
    unsigned short cantidad;
}domains;

// -----------------Prototypes----------------------

void findDomain ( char *, char * );
int compareDomains( const void *, const void * );
void lowerCase( char * );
void registroDominio( const users *, domains *, int );
int compareFrequency( const void *, const void* );

// ---------------Main Program-----------------------
int main(void)
{
    users typeDomain[10000];
    domains arrayDominios[10000];
    int i = 0;
    int total;

// --------------------------Input----------------------
    
    while ( i < 10000)
    {
        scanf("%320s", typeDomain[i].mail);
        if ( strcmp(typeDomain[i].mail, "FIN") == 0)
            break;
        i++;
    }
    
    // -----------------------Process-----------------------
    
    total = i;
    for (i = 0 ; i < total ; i++)
        findDomain(typeDomain[i].mail, typeDomain[i].domain);
    
    for (i = 0 ; i < total  ; i++)
        lowerCase(typeDomain[i].domain);
    
    
    qsort(typeDomain, total, sizeof(users), compareDomains);
    
    
    for (i = 0 ; i < total ; i++)
        printf("mail: %s  y dominio: %s\n", typeDomain[i].mail , typeDomain[i].domain);
    printf("\n\n");
    
    registroDominio( typeDomain, arrayDominios, total);
     
    return 0;
}

void registroDominio( const users *type, domains *array, int total)
{
    short i, j = 0;
    unsigned short suma = 1;
    int cant = 0;
    
    for (i = 0 ; i < total  ; i++)
    {
        if ( strcmp( type[i].domain, type[i + 1].domain) == 0)
            suma ++;
        else
        {
            strcpy(array[j].dominio, type[i].domain);
            array[j].cantidad = suma;
            suma = 1;
            cant ++;
            j ++;
        }
    }
    
    total = cant;
    /*
    for (i = 0 ; i < total ; i++)
        printf("%s : %hu\n", array[i].dominio, array[i].cantidad );*/
    
    qsort(array, total, sizeof(domains), compareFrequency);
    printf("\n\n");
    for (i = 0 ; i < total ; i++)
        printf("%s : %hu\n", array[i].dominio, array[i].cantidad );
    
}

/* -------------------------Procedimiento findDomain-------------------------------
 * Propósito: encontrar el dominio de un correo electrónico. Ejemplo: 
 * pedro@hotmail.com, el dominio es: hotmail.com 
 * 
 */

void findDomain ( char *mail, char *domain)
{
    char *pointer;
    pointer = mail;
    pointer = strchr(mail, '@');
    strcpy(domain, pointer + 1);
}

int compareDomains( const void *pivot, const void *element )
{
    users *ptrPivot = (users *) pivot;
    users *ptrElement = (users *) element;
    return strcmp( ( ptrPivot -> domain ), ( ptrElement -> domain ) );
}

int compareFrequency( const void *pivot, const void *element )
{
    domains *ptrPivot = (domains *) pivot;
    domains *ptrElement = (domains *) element;
    
    return (ptrElement -> cantidad) - (ptrPivot -> cantidad);
}

void lowerCase( char *domain)
{
    while ( *domain != '\0')
    {
        if ( isupper( *domain ) )
            *domain = tolower(*domain);
        domain ++;
    }
}

Show compiler warnings [ + ] Compiler args [ - ] Show input
Compilation time: 0.26 sec, absolute running time: 0.23 sec, cpu time: 0.14 sec, memory peak: 3 Mb, absolute service time: 0,5 sec