case 1:                                  //功能一：查找
    printf ("请输入您要查找的联系人姓名:");
    scanf ("%s",namex);
 for (i=0;i<n;i++)
 {
  if (strcmp(namex,persons[i].name)!=0)
     {
     printf ("此通讯录中没有您输入的人，请重新输入:\n");
     }
  else if (strcmp(namex,persons[i].name)==0)
  {
    printf ("\n");
    printf ("姓名:%s\n",persons[i].name);
    printf ("生日:%d.%d.%d\n",persons[i].birth.year,persons[i].birth.month,persons[i].birth.day);
    printf ("联系电话:");
    puts(persons[i].phonenumber);
    printf ("住址:");
    puts(persons[i].address);
    printf ("\n");
    break;
  }
 }
 break;

具体怎么加循环