エラトステネスの篩を実装したかったが断念

eratosthenes.c

#include<stdio.h>
#include<stdlib.h>
#include<math.h>

#define LEN 1000
#define PRIME int


struct list{
    struct list *next;
    int num;
};


void p_init(PRIME *p);
int* prime_f(PRIME *p);
void clean(int n,PRIME *p);
void show(struct list *l);



int
main(int argc, char **argv)
{
PRIME list[100];
int *p = NULL;

p_init(list);

p = prime_f(list);

return 0;
}


void p_init(PRIME *p)
{
    int i;
    for(i=0; i < LEN;i++)
    {
        *(p+i) = 1;
    }

}
/*
void push(int n, struct list *p)
{
    if( p == NULL)
    {
    p = (struct list*)malloc( sizeof(struct list*) );

    }else{

    p->next = (struct list*)malloc( sizeof(struct list*) );
    p = p->next;
    }
    p->num = n;
    p->next = NULL;

}
*/
void push(int n, int *p)
{
    *(p+n) = n;

}


void clean(int n,PRIME *p)
{
    int i;

    for(i =0; i <= (int)sqrt(LEN); i = i +n)
    {
        *(p+i)=0;
    }


}

int* prime_f(PRIME *p)
{
    int i,a=0;
    int array[LEN];

    for(i = 0; i < (int)sqrt((double)LEN); i++)
    {
        if( *(p+i) == 1 )
        {
            push(i,array);
            clean(i,p);

        }
    }

    return array;

}

void show(struct list *l)
{
    struct list *p =l;
    while(p != NULL)
    {
        printf("%d ",p->num);
        p = p->next;
    }
}