Nested array structures in C

Question

Below is the error that it is giving me and my code:

workspace.c: In function 'main':

workspace.c:38: error: subscripted value is neither array nor pointer

workspace.c:39: error: subscripted value is neither array nor pointer

any input would be greatly appreciated! and thank you for you time.

#include <stdio.h>
#include <stdbool.h>
#include <stdlib.h>
#include <sys/types.h>
#include <string.h>
#include <dirent.h>
#include <sys/time.h>
#include <fcntl.h>

#define n 4
struct process
{
    struct segment{

        struct page
        {
            int pid;
            int p[4];
        }pages;
    }segments;
};

struct process processes[3];
struct page pages[n];
struct segment segments[n];

int main()
{
    int a, b, c;
    int k = 0;
     for(a = 0; a < 3; a++)
     {
            for(b = 0; b < 4; b++)
        {
            for(c = 0; c < 4; c++)
            {
                k++;
                processes[a].segments[b].pages[c].pid = k;
                printf("Segment: %d, Page: %d, PID: %d\n",a,b,processes[a].segments[b].pages[c].pid);
            }
        }

 }

return 0;
}

#defineing something as short as n is a bit dangerous, as it could lead to substitutions you didn't intend. C tradition is to use all upper case and something descriptive, such as #define MAX_PAGES 4 — Stephen P
– Stephen P, Commented Nov 15, 2013 at 18:34

Gabriel L. · Accepted Answer · 2013-11-15 18:29:53Z

1

See this code : Tested with no error

#define n 4
struct process
{
    struct segment{

        struct page
        {
            int pid;
            int p[4];
        }pages[n];
    }segments[n];
}processes[3];


int main()
{
    int a, b, c;
    int k = 0;
     for(a = 0; a < 3; a++)
     {
        for(b = 0; b < 4; b++)
        {
            for(c = 0; c < 4; c++)
            {
                k++;
                processes[a].segments[b].pages[c].pid = k;
                printf("Segment: %d, Page: %d, PID: %d\n",a,b,processes[a].segments[b].pages[c].pid);
            }
        }

     }

    return 0;
}

answered Nov 15, 2013 at 18:29

Gabriel L.

5,0645 gold badges30 silver badges34 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Key Over a year ago

Thanks Gabriel and Mah for your help. I fixed the code. And Thanks Stephen for the input. I will change my naming convention when I #define next time.

mah Over a year ago

@Key you seem to have gone back and forth deciding which answer to accept. It would be nice to at least up vote whichever you're not accepting since you can only accept one. Glad you got the help you needed.

mah · Accepted Answer · 2013-11-15 18:25:31Z

0

Your segments element is shown as only being a single structure. Your diagram (and the way you seem to intend to use it) suggests it should be an array of them, like:

struct process
{
    struct segment{

        struct page
        {
            int pid;
            int p[4];
        }pages;
    }segments[4];   // <-------- [4]
};

You're also declaring:

struct page pages[n];
struct segment segments[n];

which you never actually use… you (rightfully, I think) use their kin inside your process structure. (This also means you're ignoring the #define n, effectively)

answered Nov 15, 2013 at 18:25

mah

40.1k9 gold badges79 silver badges94 bronze badges

Collectives™ on Stack Overflow

Nested array structures in C

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related