linker command failed 请问错在哪里呢

#include<stdlib.h>
#include<string.h>
struct www
{
    int num;
    union
    {
        int i;
        double j;
        char c[10];
    }catagory;
    enum type{Interger=1,Real,String}ccc;
    struct www*next;
};
enum type pri;
int main()
{
    void countt(struct www*p1,struct www*p2);
    void print(struct www*p2);
    void sort(struct www*pp);
    struct www*head;
    struct www*p1,*p2;
    p1=p2=(struct www*)malloc(15);
    int n=0;
    int i;
    head=NULL;
    while(n<=7)
    {
        n++;
        if(n==1)head=p1;
        else p2->next=p1;
        switch(n)
        {
            case 1:strcpy(p1->catagory.c,"banana");
                p1->ccc=String;break;
            case 2:strcpy(p1->catagory.c,"apple");p1->ccc=String;break;
            case 3:p1->catagory.i=122;p1->ccc=Interger;break;
            case 4:p1->catagory.j=67.89;p1->ccc=Real;break;
            case 5:p1->catagory.j=22.45;p1->ccc=Real;break;
            case 6:strcpy(p1->catagory.c,"orange");p1->ccc=String;break;
            case 7:p1->catagory.i=98;p1->ccc=Interger;break;
        }
        p2=p1;
        p1=(struct www*)malloc(15);
        print(p2);
    }
    p1=head;
    p2=head;
    sort(p1);
    countt(p1,p2);
    for(i=1;i<=7;i++)
        free(p1+i);
    return 0;
}
void print(struct www*p2)
{
    if(p2->ccc==String)
        printf("%-6s",p2->catagory.c);
    if(p2->ccc==Interger)
        printf("%-6d",p2->catagory.i);
    if(p2->ccc==Real)
        printf("%-6lf",p2->catagory.j);
    printf("\n");
}
void countt(struct www*p1,struct www*p2)
{
    int i,j=0,n=0,k=1;
    struct www* temp,*head;
    for(i=1;i<=7;i++)
    {
        p1->num=i;
        p1=p1->next;
    }
    head=temp=p2;
    while(j<=6)
    {
        j++;
        while(k%3!=0)
        {
            n++;
            if(n==1&&p1->num!=0)
            {
                temp=p1;
                head=temp;
            }
            else if(p1->num!=0)
                temp->next=p1;
            if(p1->next==NULL)
            {
                p1=head;
                n=0;
            }
            else p1=p1->next;
            k++;

        }
        if(p1->next==NULL)
        {
            p1=head;
            n=0;
        }
        else p1=p1->next;
        k++;
    }
    printf("最后剩下的列表编号为%d\n内容为",temp->num);
    switch(temp->num)
    {
        case 1:printf("%s",temp->catagory.c);break;
        case 2:printf("%s",temp->catagory.c);break;
        case 3:printf("%d",temp->catagory.i);break;
        case 4:printf("%lf",temp->catagory.j);break;
        case 5:printf("%lf",temp->catagory.j);break;
        case 6:printf("%s",temp->catagory.c);break;
        case 7:printf("%d",temp->catagory.i);break;
    }
}

显示linker command failed ，但是我找不出错误 可以帮帮忙吗 谢谢