Structure of a program

Hi,

I'm working on my first (100 line+) program, i've been reading alot(hole day)
and the problem is the build up of the program and functions that passes information between eachother.

I first made all my vars Globals and everything would run. Since i understood this wasen't the way your ment to program thinks i would make something else. could somebody post a example program post on a structure, point to it and printing a string from another function change the string and give it back to the structure. or just how to get a pointer to a structure and able to update it from any location?

Stef

What's wrong with the FAQ?
http://faq.cprogramming.com/cgi-bin/...&id=1073086407

I did read the faq but I don't understand the faq or the faq doesn't understand me :p
I'm realy having trouble with the pointing to the struct.

I tried to do something very easy, read from the struct(Both in Main & the function). and then write a character to players->symbol.

Code:

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#include <stdio.h>

        struct {                                                /* Struct used to store names of 2 players and a symbol. */
    char Player1[25];              /* Name of the first player */
    char Player2[25];            /* Name of the second player */
    char activePlayer[25];      /* Name of the active player. */
        char symbol;                                /* symbol of theplayer eg. 'O' */
}players={"name1", "name2", "Active",'O'}; //One record players init names and O we only need 1 row since we use vars.

//pointers
struct players *player;                                        //Player points to players.

//Prototypes
void print_person ( struct players *player );

int main( struct players *player){                //parameters for main is the pointer value leading to players

      printf ( "Player1:  %s\n", (*player).Player1 );        //print the value of player1 on the screen
      printf ( "Player2:    %s \n", player->Player2 );        //print the value of player2 on the screen(other syntax does the same thing)
      printf ( "Symbol: %c\n", player->symbol );                        //print the symbol on the screen.
      //scanf("%c",players.symbol);                                                //Can't do?
      print_person ( &players );                                                        //pass to another function.
      return 0;
}

void print_person ( struct players *player )
{
      printf ( "Name:  %s\n", player->Player1 );
      printf ( "Symbol:    %s \n", (*player).Player2 );
}

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Returns 5 errors and 1 warning:

Code:

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Compiling...
game.c
\visual studio 2005\projects\game.c(18) : error C2037: left of 'Player1' specifies undefined struct/union 'players'
\visual studio 2005\projects\game.c(19) : error C2037: left of 'Player2' specifies undefined struct/union 'players'
\visual studio 2005\projects\game.c(20) : error C2037: left of 'symbol' specifies undefined struct/union 'players'
\visual studio 2005\projects\game.c(22) : warning C4133: 'function' : incompatible types - from '*__w64 ' to 'players *'
\visual studio 2005\projects\game.c(27) : error C2037: left of 'Player1' specifies undefined struct/union 'players'
\visual studio 2005\projects\game.c(28) : error C2037: left of 'Player2' specifies undefined struct/union 'players'
4OpEenRij - 5 error(s), 1 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

---

I'm doing something terrible wrong, or I implent a tought of myself totaly wrong please enlighten me :d

Code:

---

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

typedef struct {                        /* Struct used to store names of 2 players and a symbol. */
    char Player1[25];          /* Name of the first player */
    char Player2[25];          /* Name of the second player */
    char activePlayer[25];      /* Name of the active player. */
    char symbol;                                /* symbol of theplayer eg. 'O' */
} players;

//pointers
players *player;                                        //Player points to players.

//Prototypes
void print_person ( players *player );

int main(void){        //parameters for main is the pointer value leading to players

player = malloc(sizeof(players));

strcpy(player->Player1, "name1");
strcpy(player->Player2, "name2");
strcpy(player->activePlayer, "Active");
player->symbol = '0';

printf ( "Player1:  %s\n", player->Player1 );  //print the value of player1 on the screen
printf ( "Player2:    %s \n", player->Player2 );        //print the value of player2 on the screen(other synt$
printf ( "Symbol: %c\n", player->symbol );                      //print the symbol on the screen.
//scanf("%c",players.symbol);                                          //Can't do?
print_person ( player );                                                        //pass to another function.
}

void print_person (players *player )
{
  printf ( "Name:  %s\n", player->Player1 );
  printf ( "Symbol:    %s \n", (*player).Player2 );
}

---

output:
Player1: name1
Player2: name2
Symbol: 0
Name: name1
Symbol: name2

you don't need to comment every line of code some things you've even commented twice.

Code:

---

//pointers
struct players *player;                                        //Player points to players.

---

just better instead of the global variable

Code:

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//pointers
players *player;                                        //Player points to players.

---

use local one

Code:

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int main(void)
{
  players* player = malloc(sizeof(*player));
  if(player == NULL)
  {
      //not enough memory
      return 1;
  }

---

Thx that indeed worked perfectly it's amazing it's working, a +-4 hours search and you guy's did it in what 10 minutes? :p

I think i leave the pointer as a global because i need it in every function.

Thx again Stef

Quote:

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i need it in every function

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Better put it as a parameter as in the sample with print_person