typedef struct //结构体 
     {
          char xh[13];
         char name[20];
         char xb[4];
         char year[4];
         char bz[10000];
      }Student;
      
   void stdudent_cx()
{
	
	 FILE *fp;
     int n,flag=0;
     char target[20],s[3]={0};
      Student Stu;
      int i,dot=0;
	 fp=fopen("student.txt","a+");
	  if(fp==NULL) 
      {
         printf("无法打开文件\n"); 
      }  
	while(dot==0)
	{
		printf("        ***请输入查询方式***");
		printf("           ***0.退出***\n");
        printf("           ***1.按学号***\n");	
	    printf("           ***2.按姓名***\n");	 
	    printf("           ***3.按性别***\n");	
	    printf("           ***4.按年龄***\n");  
		scanf("%d",&n);
	    while(n!=0)
	     {				
	         if(n==1)
	             {
	                  printf("退出按0\n");printf("请输入学号\n");
	                 gets(target);	 
	            }
	          else if(n==2)
	            {
                     printf("退出按0\n");printf("请输入姓名\n");
                     gets(target);	 
	            }
	        else if(n==3)
	            {
	                printf("退出按0\n");printf("请输入性别\n");
                    gets(target); 
	            }
	          else if(n==4)
	            {
	                printf("退出按0\n");printf("请输入年龄\n");
	                gets(target);
	             }
	         gets(target);
        	if(strcmp(target,s)!=0)
	         {  
	             while(!feof(fp))
	                 {
	                     fscanf(fp,"%s %s %s %s %s",Stu.xh,Stu.name,Stu.xb,Stu.year,Stu.bz);
	                     if(strcmp(target,Stu.xh)==0||strcmp(target,Stu.name)==0||strcmp(target,Stu.year)==0||strcmp(target,Stu.xb)==0)
	                        {
	                              printf("%s %s %s %s %s\n",Stu.xh,Stu.name,Stu.xb,Stu.year,Stu.bz);
                                 flag=1;
	                        }
	              
	                 }
	        }
	        else
	          {
	             dot=1;flag=1;n=0;
	          }
	       if(flag==0)
	        {
	             printf("no find\n");
	        }
	         n=0;
        }
	    if(n==0)
	    {
		   dot=1;
	    }
	}	
}


void stdudent_sc()
{
         FILE *fp;
            int dot=1;
            char target[20]; 
            Student Stu;
            fp=fopen("student.txt","a+");
			while(dot==1)	
			{
				printf("输入学号,退出按确定");
				scanf("%s",target);	
				 	FILE *out;out=fopen("back.txt","w"); /*out是充当临时文件作用*/
				 	while(!feof(fp))
				 	{
				 			if(strcmp(target,Stu.xh)!=0)
				 		{
				 			fprintf(out,"%s %s %s %s %s",Stu.xh,Stu.name,Stu.xb,Stu.year,Stu.bz);
				 			fprintf(out,"\n");
						  } 
				 		fscanf(fp,"%s %s %s %s %s",Stu.xh,Stu.name,Stu.xb,Stu.year,Stu.bz);
					 }
					 fclose(out); 
				 dot=0; fclose(fp);  
			}
}