C/Visual C - ejercicio para un certamen

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#define DATA_FILE "data.txt"

#define MAX_PERSON 256

#define MAX_NAME_LEN 32

#define MAX_LINE_LEN 256

#define MAX_DISPLAY 5

struct PERSON

{

    int id;

    char lastName[MAX_NAME_LEN];

    char firstName[MAX_NAME_LEN];

    int age;

} person[MAX_PERSON];

int readPerson(void);

void printPerson(int from, int to);

int isPersonRepeated(int id, int max);

float ageProm(int max);

double ageDesv(int media, int max);

int main( int argc, char **args)

{

    int max = readPerson();

    int from = 0;

    int to = MAX_DISPLAY;

    if( max )

    {

        do

        {

            printPerson( from, to );

            from += MAX_DISPLAY;

            to = (to + MAX_DISPLAY > max) ? max : to + MAX_DISPLAY;

            puts( "Press to continue..");

        }while( getchar() && from < max );

        printf( "Age prom : %.2f\n", ageProm( max ) );

        printf( "Age desv : %.2f\n", ageDesv( ageProm(max), max ) );

        printf( "Readed   : %d\n", max + 1);

    }

    else

        puts( "Empty file" );

    return EXIT_SUCCESS;

}

int readPerson(void)

{

    FILE *file;

    char line[MAX_LINE_LEN];

    int pNum = 0;

    int idTmp;

    if( (file = fopen( DATA_FILE, "r" )) == NULL)

    {

        puts( "Error : can\'t open file" );

        exit( EXIT_FAILURE );

    }

    while ( fgets(line, MAX_LINE_LEN, file) != NULL && pNum < MAX_PERSON )

    {

        sscanf( line, "%d", &idTmp);

        if( isPersonRepeated( idTmp, pNum ) )

            continue;

        sscanf( line, "%d %s %s %d", 

        &person[pNum].id, 

        person[pNum].lastName,

        person[pNum].firstName,

        &person[pNum].age );

        pNum++;

    }

    return pNum;

}

void printPerson(int from, int to)

{

    int i;

    if ( to <= 0 ) return;

    printf( "ID\tLastName\tFirstName\tAge\n\n" );

    for( i=from; i<to; i++ )

    {

        printf( "%-3d\t%-15s\t%-15s\t%-5d\n" ,

        person[i].id, 

        person[i].lastName,

        person[i].firstName,

        person[i].age);

    }     

}

int isPersonRepeated(int id, int max)

{

    int i;

    for( i=0; i<max; i++)

        if( id == person[i].id )

            return 1;

    return 0;    

}

float ageProm(int max)

{

    int count;

    int sum = 0;

    for( count=0; count<max; count++)

        sum += person[count].age;

    return (float) sum / count;

}

double ageDesv(int media, int max)

{

    int i;

    double sumDesv = 0;

    int ageTmp;

    for( i=0; i<max; i++)

    {

        ageTmp = person[i].age;

        sumDesv += pow( (ageTmp - media), 2);

    }

    return sqrt( sumDesv / i);      

}