编写c项目程序 员工绩效有编号（int）、姓名（字符数组）、部门（字符数组）、绩效分数（float）等属性 使用结构体表示员工绩效 使用全局结构体数组存放绩效数据（最多1000个员工） 再定义一个全局结构体数组用来排序； 定义一个表示实际记录数量的全局变量（初值为0） 功能要求：  创建员工绩效记录  显示所有员工绩效记录  清空所有记录  创建员工绩效记录  显示所有员工绩效记录  清空所有记录  保存记录到文件  从文件读取员工绩效记录  查询员工绩效记录  删除员工绩效记录  添加一个员工绩效记录  修改员工绩效记录  绩效排名 并解释代码含义

以下是一个简单的员工绩效管理程序的示例代码：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_EMPLOYEE 1000

typedef struct {
    int id;
    char name[30];
    char department[30];
    float score;
} Employee;

Employee employees[MAX_EMPLOYEE];
Employee sorted_employees[MAX_EMPLOYEE];
int num_employees = 0;

void create_employee() {
    if (num_employees >= MAX_EMPLOYEE) {
        printf("Cannot add more employees.\n");
        return;
    }

    printf("Enter employee ID: ");
    scanf("%d", &employees[num_employees].id);

    printf("Enter employee name: ");
    scanf("%s", employees[num_employees].name);

    printf("Enter employee department: ");
    scanf("%s", employees[num_employees].department);

    printf("Enter employee score: ");
    scanf("%f", &employees[num_employees].score);

    num_employees++;
}

void display_employees() {
    printf("ID\tName\tDepartment\tScore\n");
    for (int i = 0; i < num_employees; i++) {
        printf("%d\t%s\t%s\t\t%.2f\n", employees[i].id, employees[i].name, employees[i].department, employees[i].score);
    }
}

void clear_employees() {
    num_employees = 0;
}

void save_employees() {
    FILE *fp;
    fp = fopen("employees.dat", "wb");
    fwrite(employees, sizeof(Employee), num_employees, fp);
    fclose(fp);
}

void load_employees() {
    FILE *fp;
    fp = fopen("employees.dat", "rb");
    if (fp) {
        num_employees = fread(employees, sizeof(Employee), MAX_EMPLOYEE, fp);
        fclose(fp);
    }
}

void search_employee() {
    int id;
    printf("Enter employee ID: ");
    scanf("%d", &id);

    for (int i = 0; i < num_employees; i++) {
        if (employees[i].id == id) {
            printf("ID\tName\tDepartment\tScore\n");
            printf("%d\t%s\t%s\t\t%.2f\n", employees[i].id, employees[i].name, employees[i].department, employees[i].score);
            return;
        }
    }

    printf("Employee not found.\n");
}

void delete_employee() {
    int id;
    printf("Enter employee ID: ");
    scanf("%d", &id);

    for (int i = 0; i < num_employees; i++) {
        if (employees[i].id == id) {
            for (int j = i; j < num_employees - 1; j++) {
                employees[j] = employees[j+1];
            }
            num_employees--;
            printf("Employee deleted.\n");
            return;
        }
    }

    printf("Employee not found.\n");
}

void add_employee() {
    if (num_employees >= MAX_EMPLOYEE) {
        printf("Cannot add more employees.\n");
        return;
    }

    Employee new_employee;

    printf("Enter employee ID: ");
    scanf("%d", &new_employee.id);

    printf("Enter employee name: ");
    scanf("%s", new_employee.name);

    printf("Enter employee department: ");
    scanf("%s", new_employee.department);

    printf("Enter employee score: ");
    scanf("%f", &new_employee.score);

    int i = num_employees;
    while (i > 0 && new_employee.score > employees[i-1].score) {
        employees[i] = employees[i-1];
        i--;
    }

    employees[i] = new_employee;
    num_employees++;
}

void sort_employees() {
    memcpy(sorted_employees, employees, num_employees * sizeof(Employee));

    for (int i = 0; i < num_employees - 1; i++) {
        for (int j = i + 1; j < num_employees; j++) {
            if (sorted_employees[j].score > sorted_employees[i].score) {
                Employee temp = sorted_employees[i];
                sorted_employees[i] = sorted_employees[j];
                sorted_employees[j] = temp;
            }
        }
    }

    printf("ID\tName\tDepartment\tScore\n");
    for (int i = 0; i < num_employees; i++) {
        printf("%d\t%s\t%s\t\t%.2f\n", sorted_employees[i].id, sorted_employees[i].name, sorted_employees[i].department, sorted_employees[i].score);
    }
}

int main() {
    int choice;

    do {
        printf("\nEmployee Performance Management System\n");
        printf("1. Create employee\n");
        printf("2. Display all employees\n");
        printf("3. Clear all employees\n");
        printf("4. Save employees to file\n");
        printf("5. Load employees from file\n");
        printf("6. Search employee\n");
        printf("7. Delete employee\n");
        printf("8. Add employee\n");
        printf("9. Sort employees by score\n");
        printf("0. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                create_employee();
                break;
            case 2:
                display_employees();
                break;
            case 3:
                clear_employees();
                printf("All employees cleared.\n");
                break;
            case 4:
                save_employees();
                printf("Employees saved to file.\n");
                break;
            case 5:
                load_employees();
                printf("Employees loaded from file.\n");
                break;
            case 6:
                search_employee();
                break;
            case 7:
                delete_employee();
                break;
            case 8:
                add_employee();
                break;
            case 9:
                sort_employees();
                break;
            case 0:
                printf("Exiting program.\n");
                break;
            default:
                printf("Invalid choice.\n");
                break;
        }
    } while (choice != 0);

    return 0;
}

这个程序使用了一个结构体类型 `Employee` 来表示员工绩效记录，包含了员工的编号、姓名、部门和绩效分数。这些记录保存在一个全局的结构体数组 `employees` 中，最多可以保存1000条记录。

程序的主菜单提供了多种操作，包括创建员工绩效记录、显示所有记录、清空所有记录、保存记录到文件、从文件读取记录、查询记录、删除记录、添加记录和排序记录。其中，添加记录和排序记录比较特殊，需要在插入新记录和排序后重新调整数组中的元素顺序。

注意，在实际应用中，可能需要增加更多的输入验证和错误处理，以保证程序的健壮性和安全性。