#define NULL 0
#include<stdio.h>

void get(int x);
struct list{
        char a;
        struct list *Next;
    };
   
int main(void)

{
   
    int b,c,d;
    printf("请问要输入几个字母:");
    scanf("%d",&b);
    get(b);
   
}

void get(int x)
{   
   
    int first,y;
    struct list *new1,*head=NULL,*current;
   
    for(first=1;first<=x;first++)
    {
        if(new1 = (struct list*)malloc(sizeof(struct list))==NULL)
        printf("ERROR!");
        
        
        
        printf("第%d个字母\n",first);
        scanf("%c",&head->a);
        new1->Next = head;
        head=new1;
        
   
   
    }
}

已经解决了。head指向的是head  而且 ==的优先级大于= 、、、