CODEWITHSUNDEEP
c
c0d3r
c0d3r

Reputation: 9

how to access members of structures through an array of pointers to those structures

i am working on a simple ' Phone index ' project. my project is made out of : structures, arrays, pointers

if've :

a structure to define persons in the index :

and three functions to create users, add them to index, display the index :

Here is my code :

// This is my structure definition

typedef struct
{
    char fname[30];
    char lname[30];
    char phnum[14];

} PERS;

// Function prototypes

PERS *  add_person(void);
PERS ** add_index(int );
void    show_index(PERS **, int );

// Function implementation

PERS * add_person(void)
{
    PERS * p = (PERS *) calloc(1,sizeof(PERS)); // Dynamic allocation.
    printf("    First name   : ");
    scanf("%s", p->fname);
    printf("    Last name    : ");
    scanf("%s", p->lname);
    printf("    Phone number : ");
    scanf("%s", p->phnum);

    return p;   // return a pointer to the structure PERS
}


PERS ** add_index(int nbr)
{
    int i = 0;
    PERS * r[nbr];  // an array of pointers to PERS structures.

    while(i < nbr)
    {
        r[i] =  add_person();  // populate the array with pointers to PERS
        i++;
        printf("\n");
    }

    return r;   // return the array
}


void show_index(PERS **rep, int nbr)   // recieve the array
{
    int i = 0;

    while(i < nbr)
    {   // display its content
        printf("\n");
        printf("    %s \n", rep[i]->fname);
        printf("    %s \n", rep[i]->lname);
        printf("    %s \n", rep[i]->phnum);
        i++;
    }
}

and of course the main program :

#include <stdio.h>
#include <stdlib.h>
#include "funcs.h"

int main()
{
    PERS ** rep =  add_index(3);   // Create an index with three items 

    printf("\n\n");

    show_index(rep,3);

    printf("\n\n");

    return 0;
}

This is my input :

First name   : friend
Last name    : name
Phone number : 4567234512

This is the error i get :

(null)
Segmentation fault (core dumped)

i've tried several solution but it's not working.

Thanks in advance.

Upvotes: 0

Views: 55

Answers (1)

Gopi
Gopi

Reputation: 19874

You know what !! you can solve your issue by changing just a single line.

PERS **r= malloc(sizeof(PERS *) * nbr);

Use pointer to pointer and return this value from the function..

Upvotes: 1

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