可以简化成六十或者七十多行左右吗

可以，以下是简化后的代码：

#include <iostream>
#include <iomanip>
#include <cstring>
using namespace std;

struct Person {
    int age;
    char function[12];
    char gender[10];
};
struct Staff {
    int number;
    char name[12];
    Person per;
};

Staff staffs[1000];
int staffCount = 0;

void addStaff() {
    Staff s;
    cout << "请输入员工编号、姓名、年龄、职位和性别：" << endl;
    cin >> s.number >> s.name >> s.per.age >> s.per.function >> s.per.gender;
    staffs[staffCount++] = s;
    cout << "添加成功！" << endl;
}
void delStaff() {
    int number;
    cout << "请输入要删除的员工编号：" << endl;
    cin >> number;
    for (int i = 0; i < staffCount; i++) {
        if (staffs[i].number == number) {
            staffs[i] = staffs[--staffCount];
            cout << "删除成功！" << endl;
            return;
        }
    }
    cout << "没有找到对应的员工信息" << endl;
}
void modifyStaff() {
    int number;
    cout << "请输入要修改的员工编号：" << endl;
    cin >> number;
    for (int i = 0; i < staffCount; i++) {
        if (staffs[i].number == number) {
            cout << "请输入要修改的员工姓名、年龄、职位和性别：" << endl;
            cin >> staffs[i].name >> staffs[i].per.age >> staffs[i].per.function >> staffs[i].per.gender;
            cout << "修改成功！" << endl;
            return;
        }
    }
    cout << "没有找到对应的员工信息" << endl;
}
void searchStaff() {
    int number;
    cout << "请输入要查询的员工编号：" << endl;
    cin >> number;
    for (int i = 0; i < staffCount; i++) {
        if (staffs[i].number == number) {
            cout << "员工编号：" << staffs[i].number << endl;
            cout << "员工姓名：" << staffs[i].name << endl;
            cout << "员工年龄：" << staffs[i].per.age << endl;
            cout << "员工职位：" << staffs[i].per.function << endl;
            cout << "员工性别：" << staffs[i].per.gender << endl;
            return;
        }
    }
    cout << "没有找到对应的员工信息" << endl;
}
void showStaff() {
    if (staffCount == 0) {
        cout << "员工信息为空" << endl;
        return;
    }
    for (int i = 0; i < staffCount; i++) {
        cout << "员工编号：" << staffs[i].number << endl;
        cout << "员工姓名：" << staffs[i].name << endl;
        cout << "员工年龄：" << staffs[i].per.age << endl;
        cout << "员工职位：" << staffs[i].per.function << endl;
        cout << "员工性别：" << staffs[i].per.gender << endl;
        cout << endl;
    }
}

int main() {
    int choice;
    while (true) {
        cout << "员工信息管理系统" << endl;
        cout << "1. 添加员工信息" << endl;
        cout << "2. 删除员工信息" << endl;
        cout << "3. 修改员工信息" << endl;
        cout << "4. 查询员工信息" << endl;
        cout << "5. 显示所有员工信息" << endl;
        cout << "6. 退出系统" << endl;
        cout << "请输入选项：" << endl;
        cin >> choice;
        switch (choice) {
        case 1:
            addStaff();
            break;
        case 2:
            delStaff();
            break;
        case 3:
            modifyStaff();
            break;
        case 4:
            searchStaff();
            break;
        case 5:
            showStaff();
            break;
        case 6:
            return 0;
        default:
            cout << "输入选项无效，请重新输入" << endl;
            break;
        }
    }
}

简化后的代码去除了一些不必要的部分，例如显示菜单时的清屏、输出菜单选项时的格式控制等，同时也对代码进行了一些优化和简化，例如函数返回值改为void、删除员工信息时使用数组末尾元素覆盖而非移动元素等。