Tags down


Problem to access members in pointer struct located in another pointer struct

By : Ahmed Imam
Date : September 16 2020, 11:00 AM
like below fixes the issue In C, x[i] is identical to *(x + i). In your case, the type of mystudents[index] is Student, not Student*.
Therefore, either use (mystudents + index)->nom or, more conventionally, mystudents[index].nom.
code :
mystudients[index]._mycursus = calloc(1, sizeof (Cursus));
mystudients[index]._mycursus[0]._notes = calloc(3, sizeof (int));

Share : facebook icon twitter icon

Pointer to first element of C struct is the same as pointer to the struct. But not in C#: Interop problem

By : user3572610
Date : March 29 2020, 07:55 AM
fixed the issue. Will look into that further You should declare two overloads of your extern function that take two different ref struct parameters.

How to access the members of a struct within a struct via a double pointer?

By : Tania Vergara
Date : March 29 2020, 07:55 AM
hope this fix your issue As part of a school assignment, I am given a structure with a double pointer to another structure inside it. I will need to be able to access the members of the nested structure within a function, but am having no luck doing so. , In the structure
code :
typedef struct
    char* ID;
    char* PassWord;
}Account, *pAccount, **ppAccount;
typedef struct
    unsigned int numAccounts;
    ppAccount accounts;
pFleaBay->accounts = calloc(pFleaBay->numAccounts, sizeof(pAccount));

How to access struct members from pointer

By : user2611308
Date : March 29 2020, 07:55 AM
will help you It's not valid to de-reference a void* pointer. The de-referencing is basically a numerical off-set from the base-pointer. If the compiler does not know what type the pointer is, how can it know the offset amount, nor is it able to decide whether the member reference is actually valid.
In your function it is cast, It looks like there's a stray &.
code :
void sendChannel(void *channel, void *fetchAddress)
    struct channel *chan = (struct channel *)channel;

    if( capChannel( chan ) == lenChannel( chan ) )
        chan->qtail->next = head;

How do I access the members of a pointer to pointer to struct?

By : Jamal Williams
Date : March 29 2020, 07:55 AM
Hope that helps Let me breakdown your problem.
In main(), Card *deck = NULL; will allocate a pointer to Card and the pointer is pointing to NULL.
code :
void createDeck(Card ** deck)
    //deck = malloc(52 * sizeof(Card *)); //deck is a double pointer pointing to memory of type Card* allocated on stack in calling function main().
    if (deck == NULL)
        fprintf(stderr, "Null pointer error\n"); //If calling function passes NULL, it means there is some issue.
    *deck = NULL; //In more complex functions, if there are other logic before doing malloc(), it it better to reset the variables with default values.

        //allocate memory for each card in deck
    //for (size_t i = 0; i < 52; i++)
    //    *(deck + i) = malloc(sizeof(Card));

    *deck = malloc(sizeof(Card)*52); //Allocate for all 52 Cards together
    if(NULL == *deck)
        fprintf(stderr, "malloc failed\n");

    //In case you want to access a card using deck variable.
    (*deck)[2].suit = hearts;

Why can't pointer to pointer, access struct members without a cast?

By : user3318258
Date : March 29 2020, 07:55 AM
around this issue In C++, I was trying to access the struct members through double pointer headref as shown below , This expression
code :
*( headref->data )
( *headref )->data
( /*(Node*)*/ *headref)->data
Related Posts Related Posts :
  • How is malloc() than free() works
  • strcpy() in c gives me segmentation fault
  • What is the best practice when declaring a user defined array?
  • Efficient Assembly multiplication
  • while (getchar != '\n'); alternative to clear the buffer
  • How to fill a number with a variable amount of 0s?
  • Why C programming gives different output?
  • How to get float value from uint32_t?
  • What is the output of expression c=a+++b? If a=2,b=5 in c language...?
  • Why does it print 1 at the end?
  • Caesar cipher for numbers in C
  • Could someone explain the method of making rules for connect 4 game in C?
  • Is it a memory leak in C when code fails to free memory, but the OS will anyway?
  • Why can't I initialize a loop with i = -1?
  • How does the fork() function behave in if statements?
  • Why strcpy_s is safer than strcpy?
  • gcc flags to disable arithmetic optimisations
  • Recursion in c to print characters
  • Character array initialization using for loop
  • C Programming - Cannot Call Function More Than Once
  • Structures and pointer to pointer element
  • Error when initializing struct members in struct definition
  • Is that fixed-size array? a[]
  • It is not outputting what was expected and am unsure as to the issue
  • i want use C shell code to make buffer overflow and execute bin/sh
  • what the main function in this program returns to os?
  • Suffixes for integer types
  • I don't understand why a equals 1 and b equals 0 in this program
  • C prints other integer number than what it shows on Watches. Why is that?
  • Output of the for loop?
  • How to find 64-bit divisions in existing C code?
  • Finding a numbers with the largest/smallest number of bits set
  • how does " for (int j = 0; j < n || !putchar('\n'); j++) " work
  • handle ctrl+c in client-server socket in c programing
  • Restrict a process to read "/etc/resolv.conf" file in linux
  • Restrict scope of global variable inside one file in C
  • Arduino AES128 encryption - decryption problem
  • Why is not ampersand needed in the following code?
  • Is it possible to define a function name with #define?
  • Why is the size of the data type different when the value is directly passed to the sizeof operator?
  • Segmentation fault / Incorrect checksum triggered ocasionally when reading lines from a file
  • Adding bits at specific indexes for a uint8_t block
  • how can I use "shadow call stack" feature of clang-8 in x86_64?
  • malloc Assertion Failed
  • Array of structs inside of another struct in C
  • Why does this print the wrong part of the string?
  • Moving the cursor and printing characters in console doesn't work with sleep
  • Confusion in adding an element to a sorted list of integers
  • How I can separate integer number in 3 "houses"? Hundred, Ten and Unity
  • User-implemented memory management
  • What it entails to declare and initialize a pointer in this way: int (*p)[n]
  • Function to look though any struct in C
  • Microcontroller not recognized at USB port when connected via pins
  • Unexpected bitshift behavior in C
  • Model 3D spring from points
  • C control reaches end of non void function
  • Tax outputting 0
  • Gtk 3.0 Text View Resizable
  • Statically linking libc into my binary causes it to segfault
  • Child Process Executing Print Statement But Nothing Afterwards
  • shadow
    Privacy Policy - Terms - Contact Us © 35dp-dentalpractice.co.uk