Thread: Need function to show values

You seem to be thinking of something like this:

Code:

#include <stdio.h>
#include <stdlib.h>
 
typedef struct N
{
    int v;
    struct N *x;
} N;
 
N *add(N *r, int v)
{
    N *n = malloc(sizeof *n);
    if (!n) { perror("add"); exit(1); }
    n->v = v;
    n->x = r;
    return n;
}
 
void print(const N *r)
{
    for ( ; r; r = r->x) printf("%d ", r->v);
    printf("\n");
}
 
int main()
{
    N *r = NULL;
    r = add(r, 1);
    r = add(r, 2);
    r = add(r, 3);
    r = add(r, 4);
 
    print(r); // values are printed in reverse order since 'add'
              // adds new elements to the head of the list
 
    return 0;
}

john.c introduced a struct type in order to construct a linked list, i.e., struct N represents a linked list node. This way, you can store the values in a linked list and thereby loop over the linked list in order to show them.

You could say, store the pointers in an array of pointers instead, and thereby loop over the array in order to show the values that the pointers point to. For example:

Code:

#include <stdio.h>

int *foo(int value)
{
    int *p = malloc(sizeof(*p));
    if (p)
    {
        *p = value;
    }
    return p;
}


void print_values(int *values[], size_t num)
{
    for (size_t i = 0; i < num; ++i)
    {
        if (values[i])
        {
            printf("%d\n", *values[i]);
        }
    }
}


int main(void)
{
    int *p[4];
    p[0] = foo(1);
    p[1] = foo(2);
    p[2] = foo(3);
    p[3] = foo(4);

    print_values(p, sizeof(p) / sizeof(p[0]));

    // free what you malloc here
    // ...

    return 0;
}