void del_account(FILE *fp,int accountnum)
{
    int i, key;
    if(search_account(fp,accountnum,1)==0)
        printf("无法找到此账户！\n");
    else
    {
    	i = search_account(fp,accountnum,0) - 1;
    	printf("请输入密码\n");
    	scanf("%d",&key);
    	while (!search_key(fp, key, i) && key != 0)
    		{
    			system("cls");
    			printf("您输入的密码有误!\n请重新输入或输入0放弃删除\n");
    			scanf("%d", &key);
    		}
    		system("cls");
    		if (key)
    		{
		        for(i = 0;i<cur_account-1;i++)
		            if(accountcollection[i].account != accountnum)
		              fprintf(fp,"%d %d %s %.2f\n",
		                      accountcollection[i].account,accountcollection[i].key,accountcollection[i].name,accountcollection[i].balance);
    			printf("注销成功!\n");
    		}
    		else
    			printf("注销失败!\n");
    }
}