sosu.c

#include
#include 

/**
 * 構造体
 */
typedef struct sosu_list {
    int no;
    struct sosu_list *next;

} SOSU_LIST;

/**
 * 構造体の素数番号を返却
 */
int get_sosu_list( SOSU_LIST *head , int no )
{
    SOSU_LIST *p = head->next;
    int count    = 0;

    while( p != NULL && count < no  )
    {
        p = p->next;
        count ++;
    }

    if( count >= no ) return p->no;
    return  -1;

}


/**
 * 素数計算
 */
void calc_sosu( SOSU_LIST *head , int max )
{
    int add_flg    = 1;
    int count      = 2;
    int sosu_count = 0;

    SOSU_LIST *list_p = head->next;
    SOSU_LIST *end_p  = head;
    SOSU_LIST *sosu_p = NULL;

    while( sosu_count < max )
    {

        list_p = head->next;
        add_flg = 1;
        while( list_p != NULL )
        {

            if( ( count % list_p->no ) == 0 )
            {
                add_flg = 0;
                break;

            }
            list_p = list_p->next;

        }

        if( add_flg == 1 )
        {
            sosu_p = ( SOSU_LIST *) malloc( sizeof( SOSU_LIST ));
            if (sosu_p == NULL) {
                return ;
            }
            sosu_p->no    = count;
            sosu_p->next  = NULL;
            end_p->next   = sosu_p;
            end_p         = sosu_p;
            sosu_count ++;
            //printf("%dn",end_p->no);

        }
        count++;

    }

}

/**
 * エントリポイント
 */
int main()
{

    SOSU_LIST head;
    head.no   = 0;
    head.next = NULL;

    calc_sosu( &head ,1001 );
    printf("1000番目の素数は%dです。n", get_sosu_list( &head, 1000));

}