Thread: Problem with copying a string into array in a struct

Now the problem I have is that when I copy strings into an array in a struct, it does it, but when I try to print the first element of the array in the struct it prints out everything that's in the array. I think you just need to look at the colour highlighted bits.

Code:

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

//3 AI's and 1 player game

typedef struct player Player;

struct player {
  
  char alias[25];    //player name
  char nCards[26];     //cards the player has
  Player *next;
};

int TCards;   //total cards

Player *newn(void); //new node (player)
//int cards (void);
int dist (void);   //distributing

int main (void) {

  dist();

  return 0;
}

int dist (void) {
  
  char *cards[] = {"2c","3c","4c","5c","6c","7c","8c","9c","10c","JC","QC","KC","AC",
                    "2s","3s","4s","5s","6s","7s","8s","9s","10s","JS","QS","KS","AS",
                    "2h","3h","4h","5h","6h","7h","8h","9h","10h","JH","QH","KH","AH",
                    "2d","3d","4d","5d","6d","7d","8d","9d","10d","JD","QD","KD","AD"};
  char *cards2[] = {"2c","3c","4c","5c","6c","7c","8c","9c","10c","JC","QC","KC","AC",
                    "2s","3s","4s","5s","6s","7s","8s","9s","10s","JS","QS","KS","AS",
                    "2h","3h","4h","5h","6h","7h","8h","9h","10h","JH","QH","KH","AH",
                    "2d","3d","4d","5d","6d","7d","8d","9d","10d","JD","QD","KD","AD"};

  /*char *p_dist[52]; //distributed cards are also copied into this array, so no recopying
  char *p_dist2[52];*/ //second array to handle doubles to prevent infinite loop from less-card distribution

  int i = 0; //indexer of array from distributor
  int j = 0;
  int arr_choice; //value can be 0 or 1, if 0, then take from cards[], if 1, from cards2[]


  Player *n_player;  //node for new players
  Player *user;      //human
  Player *ai_1;
  Player *ai_2;
  Player *ai_3;

  puts("Creating AI's and User...");

  n_player = newn();
  user = n_player;
  n_player = newn();
  ai_1 = n_player;
  n_player = newn();
  ai_2 = n_player;
  n_player = newn();
  ai_3 = n_player;

  puts("\nEnter your name");
  scanf("&#37;25s", user->alias);
  puts("\nEnter 1st AI's name");
  scanf("%25s", ai_1->alias);
  puts("Enter 2nd AI's name");
  scanf("%25s", ai_2->alias);
  puts("Enter 3rd AI's name");
  scanf("%25s", ai_3->alias);


  printf("\n\nDistributing cards to %s...\n\n", user->alias);
  srand ( time(NULL) );         //seed
  TCards = 0;  //indexer for controlling cards that go to user

//////////////////*THIS IS THE DISTRIBUTION LOOP FOR THE HUMAN USER*/////////////////
  for (TCards=0; TCards < 25; TCards++){   //104 / 4 = 26 cards per user
    arr_choice = rand()/(int) (((unsigned)RAND_MAX + 1)/ 2);
    if(arr_choice == 0) {
      i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      while(strcmp(cards[i], "0") == 0) {
        i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      }
      strcpy(&user->nCards[j], cards[i]);
      cards[i] = "0";
      j++;
    }
    else if(arr_choice == 1) {
      i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      while(strcmp(cards2[i], "0") == 0) {
        i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      }
      strcpy(&user->nCards[j], cards2[i]);
      cards[i] = "0";
      j++;
    }
  }
  int b = 0;
  [B]printf("%s\n", &user->nCards);
  return 0;
}

Player *newn(void) {
  
  Player *player;
  player = (Player*)malloc(sizeof(Player));
  
  return (player);
}

So essentially instead of the first element printing say: "2s"

It will print 2s3dfJK3d...etc etc.

I think it's because of the way I've used the pointers. How do I fix this?

Thanks

EDIT: Don't ask me why [b] comes before printf, it's not like that in the code, the formatting doesn't work too well when I tried editing here.

Perhaps you want
char nCards[26][3];

And
printf("%s\n", user->nCards[0] );

Code:

>  char nCards[26];

nCards need to be two dimensional, so you can store more than one card, each card being a string.

Code:

  char nCards[26][3];

Why does it need to be [26][3] ? What is the [3] for ?

The user gets only 26 cards, so isn't [26] enough for storing the cards? Where each card is indicated by a string, so 26 cards, 26 strings.

The two dimensional seems to work, but not properly, sometimes I get garbage values. I can't use char *nCards[26]

That doesn't work.

That doesn't work.

You mean - you haven't found yet a correct way to make it work...

Originally Posted by vart

You mean - you haven't found yet a correct way to make it work...

Not really, I tried that several times before with varying things, it didn't work, so I assumed it didn't.

Originally Posted by JFonseka

Not really, I tried that several times before with varying things, it didn't work, so I assumed it didn't.

You assume wrong - there's certainly a way to make it work, because a 2D array can ALWAYS be replaced with an array of pointers - you obviously have to make the pointers point to some suitable memory, but it certainly can be done.

--
Mats

Well I get segmentation faults that way, do I need to malloc before strcpy ?

Did that too now, it works a lot better, except it randomnly segfaults sometimes.

If you post the code, we will be much better equipped to help you.

--
Mats

Code:

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

//3 AI's and 1 player game

typedef struct player Player;

struct player {
  
  char alias[25];    //player name
  char *nCards[26];     //cards the player has
  Player *next;
};

int TCards;   //total cards

Player *newn(void); //new node (player)
//int cards (void);
int dist (void);   //distributing

int main (void) {

  dist();

  return 0;
}

int dist (void) {

  char *cards[] = {"2c","3c","4c","5c","6c","7c","8c","9c","Tc","JC","QC","KC","AC",
                    "2s","3s","4s","5s","6s","7s","8s","9s","Ts","JS","QS","KS","AS",
                    "2h","3h","4h","5h","6h","7h","8h","9h","Th","JH","QH","KH","AH",
                    "2d","3d","4d","5d","6d","7d","8d","9d","Td","JD","QD","KD","AD"};
  char *cards2[] = {"2c","3c","4c","5c","6c","7c","8c","9c","Tc","JC","QC","KC","AC",
                    "2s","3s","4s","5s","6s","7s","8s","9s","Ts","JS","QS","KS","AS",
                    "2h","3h","4h","5h","6h","7h","8h","9h","Th","JH","QH","KH","AH",
                    "2d","3d","4d","5d","6d","7d","8d","9d","Td","JD","QD","KD","AD"};

  /*char *p_dist[52]; //distributed cards are also copied into this array, so no recopying
  char *p_dist2[52];*/ //second array to handle doubles to prevent infinite loop from less-card distribution

  int i = 0; //indexer of array from distributor
  int j = 0;
  int arr_choice; //value can be 0 or 1, if 0, then take from cards[], if 1, from cards2[]


  Player *n_player;  //node for new players
  Player *user;      //human
  Player *ai_1;
  Player *ai_2;
  Player *ai_3;

  puts("Creating AI's and User...");
  // THINGS FINALLY STOPPED GIVING SEG FAULTS, CHECK SIZE OF ALLOCATION
  n_player = newn();
  user = n_player;
  n_player = newn();
  ai_1 = n_player;
  n_player = newn();
  ai_2 = n_player;
  n_player = newn();
  ai_3 = n_player;

  puts("\nEnter your name");
  scanf("&#37;25s", user->alias);
  puts("\nEnter 1st AI's name");
  scanf("%25s", ai_1->alias);
  puts("Enter 2nd AI's name");
  scanf("%25s", ai_2->alias);
  puts("Enter 3rd AI's name");
  scanf("%25s", ai_3->alias);


  printf("\n\nDistributing cards to %s...\n\n", user->alias);
  srand ( time(NULL) );         //seed
  TCards = 0;  //indexer for controlling cards that go to user

//////////////////*THIS IS THE DISTRIBUTION LOOP FOR THE HUMAN USER*/////////////////
  for (TCards=0; TCards < 25; TCards++){   //104 / 4 = 26 cards per user
    arr_choice = rand()/(int) (((unsigned)RAND_MAX + 1)/ 2);
    if(arr_choice == 0) {
      i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      while(strcmp(cards[i], "0") == 0) {
        i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      }
      user->nCards[j] = malloc(strlen(cards[i])*sizeof(char*));
      strcpy(user->nCards[j], cards[i]);
      cards[i] = "0";
      j++;
    }
    else if(arr_choice == 1) {
      i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      while(strcmp(cards2[i], "0") == 0) {
        i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      }
      user->nCards[j] = malloc(strlen(cards2[i])*sizeof(char*));
      strcpy(user->nCards[j], cards2[i]);
      cards[i] = "0";
      j++;
    }
  }
  int b;
  for (b=0;b<25;b++){
    printf("%s\n", user->nCards[b]);
  }  

/////////////////////*THIS IS THE DISTRIBUTION LOOP FOR AI 1////////////////////
  printf("\n\nDistributing cards to %s...\n\n", ai_1->alias);
  j = 0;
  for (TCards=0; TCards < 25; TCards++){   //104 / 4 = 26 cards per user
    arr_choice = rand()/(int) (((unsigned)RAND_MAX + 1)/ 2);
    if(arr_choice == 0) {
      i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      while(strcmp(cards[i], "0") == 0) {
        i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      }
      ai_1->nCards[j] = malloc(strlen(cards[i])*sizeof(char*));
      strcpy(ai_1->nCards[j], cards[i]);
      cards[i] = "0";
      j++;
    }
    else if(arr_choice == 1) {
      i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      while(strcmp(cards2[i], "0") == 0) {
        i = rand()/(int) (((unsigned)RAND_MAX + 1)/ 53);
      }
      ai_1->nCards[j] = malloc(strlen(cards2[i])*sizeof(char*));
      strcpy(ai_1->nCards[j], cards2[i]);
      cards[i] = "0";
      j++;
    }
  }
  for (b=0;b<25;b++){
    printf("%s\n", ai_1->nCards[b]);
  }
  return 0;
}

Player *newn(void) {
  
  Player *player;
  player = (Player*)malloc(sizeof(Player));
  
  return (player);
}

nCards[j], is a pointer - you should not use strcpy just
ai_1->nCards[j] = cards2[i];

no need to malloc as well

also char *cards2
should be declared as
const char *cards2
as all other const char pointers used

if instead of
cards[i] = "0";
you will use cards[i] = NULL;
your check
strcmp(cards2[i], "0") == 0
could be made shorter:
cards[i] == NULL