素数为只能被自己和1整除的数.如果i j等于0,说明i不是素数,跳 出本层循环-Prime number can only be yourself and divisible if i j is equal to 0, indicating that i is not prime, jumped out of the loop

通讯录管理系统，可以实现查询，删除，储存，修改等重要功能-Contact management system that can achieve query, delete, store, modify, and other important functions