Commentaires sur code source (long)

Bonjour à tous,

J'suis rentré de vacanes et me revoici avec mes exos de C. Cette fois ci
crée une structure pour stocker les informations d'un vol.

Si vous avez tout commentaire sur le code, de manière à l'améliorer,
faites en part :-).

/*-8<-----------------------------------------------------------------

flight_reservation.c -- This program simulate a flight reservation

Author : Eddahbi Karim
E-mail : non.tu.ne.me.connais.pas.spavrai@ifrance.com Nick :
ThE_TemPLaR (newsgroups/Forums)

----------------------------------------------------------------------

Usage : Launch the program and enter the airport codes,
the flight number, the starting time and the arrival time.

Warning : Time must contain 2 digits : 2 digits. Not more, not
less.

----------------------------------------------------------------->8-*/

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

/*--------------------------------------------------------------------

USAGE : Calculate the first dimension of a two dimensions array

PARAMETER : Two dimensional array

--------------------------------------------------------------------*/

#define FIRST_DIM_SIZE(array) sizeof((array)) / sizeof((array[0]))

/************************Structures***********************************

Reservation

Contains :
- flight_nb[6] : The flight number ( 4 digits max )
- orig_air_code[5] : The origin airport code ( 3 letters )
- dest_air_code[5] : The destination airport code ( 3 letters )
- start_time[7] : Starting time [2 digits : 2 digits]
- end_time[7] : Arrival time [2 digits : 2 digits]

*********************************************************************/

typedef struct {
char flight_nb[6];
char orig_air_code[5];
char dest_air_code[5];
char start_time[7];
char end_time[7];
} reservation;

/*********************************************************************

NAME : wipestring( string )

USAGE : Wipe useless values from the string...

PARAMETERS : char const *string to wipe...

*********************************************************************/

static void
wipestring (char const *string)
{
/* We search a '\n' character */
char *p = strchr (string, '\n');

/* We found it, we replace it by '\0' */ if (p)
{
*p = '\0';
}

/* We don't find it, so we get everything pending in stdin */ else
{
int c;

while ((c = getchar ()) != '\n' && c != EOF) {
}
}
}

/*********************************************************************

NAME : getstring ( string, size )

USAGE : Take the user input and verify it...

PARAMETERS :
- The string to check and to fill if the user enter something - The
size of the string

RETURNS (int) :
- EXIT_SUCCESS
- EXIT_FAILURE

*********************************************************************/

static int
getstring (char *string, size_t size) {
/* The error number */
int err = EXIT_SUCCESS;

/* Check if there's an input */
if (fgets (string, (int) size, stdin) == NULL) {
(void) printf ("Input Error\n");
err = EXIT_FAILURE;
}

else
{
/* Is the input too large ? */
if ( strchr(string, '\n') == NULL )
{
(void) printf("Input too large.\n");
wipestring(string);
err = EXIT_FAILURE;
}

/* If we got a '\n', does he enter something ? */ if ( err ==
EXIT_SUCCESS )
{

/* Wipe useless values */
wipestring (string);

if (*string == '\0')
{
(void) printf ("No input\n");
err = EXIT_FAILURE;
}

}
}

return err;
}

/*********************************************************************

NAME : get_answer( *string, input_size )

USAGE : Print an input area with a space determined by the size of
the value to take and take the value.

PARAMETERS :
- The string to store the input.
- The size of this input.

RETURNS (int) :
- EXIT_SUCCESS
- EXIT_FAILURE

*********************************************************************/

static int
get_answer ( char *string, size_t input_size ) {
/* Exit status */
int err = EXIT_SUCCESS;

/* Variable used for repetitions */
size_t i = 0;

/* If we can't write anything in the string, this is useless */ #ifdef
DEBUG
if ( input_size < 3 )
{
(void) fprintf(stderr, "Input size allocated too small !"); err =
EXIT_FAILURE;
} else
#endif /* DEBUG */

{

/* Information about the number of char authorized */ (void)
printf("(%d char max)", (int) input_size - 2);

(void) printf("[");

/* sizeof returns the real size of an array, but for a string
we got 2 reserved places ( "string\n\0" ) */

/* Design the input area */
for (i = 0; i < input_size - 2; i++ ) {
(void) printf("-");
}

(void) printf("]");

/* stdin got ( input_size - 2 ) + 1 char, to put the user
inside the input area we go (input_size - 1) chars back */

/* Put the user inside the input area */ for (i = 0; i <
input_size - 1; i++ ) {
(void) printf("\b");
}


}

/* If nothing is wrong, grab the user value */ if ( err ==
EXIT_SUCCESS )
{
err = getstring(string, input_size);
}

return err;

}

/*********************************************************************

NAME : checkcode ( *string, input_size )

USAGE : Check the airport code entered by the user.

PARAMETERS :
- The airport code
- Its size.

RETURNS (int) :
- EXIT_SUCCESS
- EXIT_FAILURE

*********************************************************************/

static int
checkcode ( char *string, size_t input_size ) {
/* Exit status */
int err = EXIT_SUCCESS;

/* The code number */
int number = 0;

/* The airport codes */
char codes[][5] = { "JPU", "NYC", "TYO", "TXL", "LCY", "HKG" };

#ifdef DEBUG

/* We check if the pointer points to something */ if ( string == NULL
)
{
(void) fprintf(stderr, "Invalid string pointer"); err =
EXIT_FAILURE;
}

/* The input_size must be equal to 5 (XXX\n\0) */ else if ( input_size
!= 5 )
{
(void) fprintf(stderr, "Input under/oversized."); err =
EXIT_FAILURE;
} else

#endif /* DEBUG*/

/* We get the airport code */
if ( err == EXIT_SUCCESS )
err = get_answer(string, input_size);

/* We check if the code is correct */ if ( err == EXIT_SUCCESS )
{
/* We reset the exit status */
err = EXIT_FAILURE;

/* The code is compared to each code in the code database */ for
(number = 0; number < FIRST_DIM_SIZE(string) + 1 &&
err != EXIT_SUCCESS; number++)
{
if ( strcmp(string, codes[number]) == 0 )
err = EXIT_SUCCESS;
}

/* If the user entered a wrong code, say it to him */ if ( err ==
EXIT_FAILURE )
(void) printf("Wrong airport code");
}

return err;
}

/*********************************************************************

NAME : checktime ( *string, input_size )

USAGE : Check if the user entered a valid time.

PARAMETERS :
- Time entered by the user
- Input size

RETURNS (int) :
- EXIT_SUCCESS
- EXIT_FAILURE

*********************************************************************/

static int
checktime (char *string, size_t input_size) {
/* Exit status */
int err = EXIT_SUCCESS;

/* Time values : Hour and minutes */
unsigned short int time[2] = { 0, 0 };

/* Debug : We check if the pointer is valid */ #ifdef DEBUG
if ( string == NULL )
{
(void) fprintf(stderr, "Invalid string pointer.\n"); err =
EXIT_FAILURE;
}

/* Debug : We check if the input_size is correct
It must be 7 ( xx:xx\n\0 ) */
else if ( input_size != 7 )
{
(void) fprintf(stderr, "Input under/oversized. Must be 7.\n"); err
= EXIT_FAILURE;
}
#endif /* DEBUG */

/* We get the time */
err = get_answer(string, input_size);

/* We verify if the user put the separator */ if ( string[2] != ':' )
{
(void) puts("Wrong separator or not placed correctly"); err =
EXIT_FAILURE;
}

/* We check if the user doesn't enter a letter at the end */ else if (
isdigit(string[4]) == 0 )
{
(void) puts("Wrong values");
err = EXIT_FAILURE;
}

/* We check if the user entered two numbers */ else if (
sscanf(string, "%02hu:%02hu", &time[0], &time[1]) != 2 ) {
(void) puts("Wrong values");
err = EXIT_FAILURE;
}

/* Are the time values correct ? */
else if ( ( time[0] > 23 ) || ( time[1] > 59 ) ) {
(void) puts("Wrong time, the maximal value for the hour is 23");
err = EXIT_FAILURE;
}

return err;

}

/*********************************************************************

NAME : ask ( *client_fl )

USAGE : Take the principal informations about the flight and do
some basic check.

PARAMETER : The client reservation data structure.

RETURNS (int) :
- EXIT_SUCCESS
- EXIT_FAILURE

*********************************************************************/

static int
ask ( reservation *client_fl )
{
/* Error status */
int err = EXIT_SUCCESS;

assert( client_fl != NULL );

/* We check if the pointer point to something */ if ( client_fl ==
NULL )
{
(void) fprintf(stderr, "Data structure pointer client_fl is
invalid"); err = EXIT_FAILURE;
}

/* If everything is ok, we ask the first question */ else {
(void) puts("What's the starting airport code :");

err = checkcode(client_fl->orig_air_code,
sizeof(client_fl->orig_air_code));
}

/* Ok ? Next question */
if ( err == EXIT_SUCCESS )
{
(void) puts("What's the destination airport code :");

err = checkcode(client_fl->dest_air_code,
sizeof(client_fl->dest_air_code));
}

/* The flight number */
if ( err == EXIT_SUCCESS )
{
(void) puts("What's your flight number :");

err = get_answer(client_fl->flight_nb,
sizeof(client_fl->flight_nb));
}

/* Starting and arrival time */
if ( err == EXIT_SUCCESS )
{
(void) puts("The flight will start at : ( Valid times are 00:00 ->
23:59 )"); err = checktime(client_fl->start_time,
sizeof(client_fl->start_time));
}

if ( err == EXIT_SUCCESS )
{
(void) puts("The plane will arrive at : ( Valid times are 00:00 ->
23:59 )"); err = checktime(client_fl->end_time,
sizeof(client_fl->end_time));
}

/* If everything is ok, we print the user's flight information */ if (
err == EXIT_SUCCESS )
{
(void) printf("You start from | %s\n"
"You'll fly to | %s\n"
"Your flight number is | %s\n"
"The plane will lift off at | %s\n"
"The plane will arrive at | %s\n",
client_fl->orig_air_code,
client_fl->dest_air_code,
client_fl->flight_nb,
client_fl->start_time,
client_fl->end_time);
}

return err;

}

/*********************************************************************

NAME : aircodes ( void )

USAGE : Display program version and airport codes.

*********************************************************************/

static void
aircodes ( void )
{
(void) puts("Flight reservation v0.1"); (void)
puts("---------------------------------------------------------");
(void) puts("Airport codes :");
(void) printf("\nJPU - Paris La Defense\n"
"NYC - New York Multiple City Code\n" "TYO - Tokyo Narita\n"
"TXL - Berlin Tegel\n"
"LCY - London City\n"
"HKG - Hong Kong Intl\n");
(void)
printf("---------------------------------------------------------\n\n");
}

int main ( void )
{
/* Final exit status */
int err = EXIT_SUCCESS;

/* The data structure which contains client flight informations */
reservation client_fl = {{0}, {0}, {0}, {0}, {0}};

/* Display the airport codes */
aircodes();

/* Get the client flight informations */ (void) puts("Welcome.");

err = ask( &client_fl );

return err;
}