#include <stdio.h>
#include <string.h>

int main()
{

  FILE* fp;
  char* p1=0;
  char* op=0;
  char* p=0;
  fp=fopen("dictionary.txt","rt");
  if(fp==0)
     {
            printf("找不到文件");
            getch();
            exit(1);
     }
  while(1)
     {
            printf("\n\n请输入关键字：");
            scanf("%s ",p1);
            while(!feof(fp))
                {
                         fscanf(fp,"%s\n",op);
                         p=strstr(op,p1);
                         if(p!=0)
                                   printf("%s\n",op);
                         op=0;
                }
             p1=0;
             fseek(fp,0L,0);
             printf("\n");                     
     }                                         
  getch();   
  return 0;
}

  fscanf(fp,"%s\n",op);中没有给op分配相应的内存空间

只有指针，没的空间，这是必然结果！

lo楼上的说的对，没有给分配空间