编写一个程序，该程序能输入职工工号、完成的产品数量、产品名称、产品种类，程序允许同一职工有多次输入，由程序对其完成的产品数量实现累计。程序按完成数量对他们排序，并确定他们的名次。按完成的产品数量由多到少的顺序，输出名次、同一名次的职工人数及他们的工号(工号由小到大顺序输出)。 要求： （1）程序用有序链表实现相关功能 （2）各类信息存储至文件 （3）修改、删除后的信息需要同步更新至文件。 （4）系统具有数据录入功能。 （5）工作量统计功能，可以分别按职工工号、产品种类。 （6）工作量排序功能。 （7）通过链表对录入的信息进行查询、修改、删除。代码

好的，以下是一个基于C语言的程序，能够实现你所需的功能：

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

// 定义职工结构体
typedef struct Employee {
    int id; // 工号
    int count; // 完成的产品数量
    char name[20]; // 产品名称
    char type[20]; // 产品种类
    struct Employee* next; // 指向下一个职工的指针
} Employee;

// 定义链表结构体
typedef struct EmployeeList {
    Employee* head; // 链表头指针
    int size; // 链表大小
} EmployeeList;

// 函数声明
void saveToFile(EmployeeList* list);
void readFromFile(EmployeeList* list);
void insertEmployee(EmployeeList* list, Employee* employee);
void addEmployee(EmployeeList* list);
void printEmployees(EmployeeList* list);
void sortEmployees(EmployeeList* list);
void countEmployee(EmployeeList* list, int id);
void countType(EmployeeList* list, char* type);
void deleteEmployee(EmployeeList* list, int id);
void updateEmployee(EmployeeList* list, int id, char* name, char* type, int count);

// 保存链表信息至文件
void saveToFile(EmployeeList* list) {
    FILE* fp = fopen("employees.txt", "w");
    if (fp == NULL) {
        printf("Failed to open file.\n");
        exit(1);
    }
    Employee* p = list->head;
    while (p != NULL) {
        fprintf(fp, "%d %d %s %s\n", p->id, p->count, p->name, p->type);
        p = p->next;
    }
    fclose(fp);
}

// 从文件中读取信息并存入链表
void readFromFile(EmployeeList* list) {
    FILE* fp = fopen("employees.txt", "r");
    if (fp == NULL) {
        printf("Failed to open file.\n");
        exit(1);
    }
    while (!feof(fp)) {
        Employee* employee = (Employee*) malloc(sizeof(Employee));
        fscanf(fp, "%d %d %s %s", &employee->id, &employee->count, employee->name, employee->type);
        employee->next = NULL;
        insertEmployee(list, employee);
    }
    fclose(fp);
}

// 将职工插入到链表中
void insertEmployee(EmployeeList* list, Employee* employee) {
    if (list->head == NULL) {
        list->head = employee;
    } else {
        Employee* p = list->head;
        Employee* q = NULL;
        while (p != NULL && p->count >= employee->count) {
            q = p;
            p = p->next;
        }
        if (q == NULL) {
            employee->next = list->head;
            list->head = employee;
        } else {
            employee->next = q->next;
            q->next = employee;
        }
    }
    list->size++;
}

// 添加职工
void addEmployee(EmployeeList* list) {
    Employee* employee = (Employee*) malloc(sizeof(Employee));
    printf("请输入工号、产品数量、产品名称、产品种类：");
    scanf("%d %d %s %s", &employee->id, &employee->count, employee->name, employee->type);
    employee->next = NULL;
    insertEmployee(list, employee);
    saveToFile(list);
}

// 输出职工信息
void printEmployees(EmployeeList* list) {
    printf("名次\t工号\t产品数量\t产品名称\t产品种类\n");
    Employee* p = list->head;
    int rank = 1;
    while (p != NULL) {
        printf("%d\t%d\t%d\t\t%s\t\t%s\n", rank, p->id, p->count, p->name, p->type);
        Employee* q = p->next;
        int count = 1;
        while (q != NULL && q->count == p->count) {
            printf("\t%d\t%d\t\t%s\t\t%s\n", q->id, q->count, q->name, q->type);
            q = q->next;
            count++;
        }
        rank += count;
        p = q;
    }
}

// 对职工按完成数量排序
void sortEmployees(EmployeeList* list) {
    Employee* p = list->head;
    list->head = NULL;
    while (p != NULL) {
        Employee* q = p->next;
        insertEmployee(list, p);
        p = q;
    }
}

// 统计某个职工的完成数量
void countEmployee(EmployeeList* list, int id) {
    Employee* p = list->head;
    int count = 0;
    while (p != NULL) {
        if (p->id == id) {
            count += p->count;
        }
        p = p->next;
    }
    printf("职工%d的完成数量为：%d\n", id, count);
}

// 统计某个产品种类的完成数量
void countType(EmployeeList* list, char* type) {
    Employee* p = list->head;
    int count = 0;
    while (p != NULL) {
        if (strcmp(p->type, type) == 0) {
            count += p->count;
        }
        p = p->next;
    }
    printf("产品种类%s的完成数量为：%d\n", type, count);
}

// 删除某个职工的信息
void deleteEmployee(EmployeeList* list, int id) {
    Employee* p = list->head;
    Employee* q = NULL;
    while (p != NULL) {
        if (p->id == id) {
            if (q == NULL) {
                list->head = p->next;
            } else {
                q->next = p->next;
            }
            free(p);
            list->size--;
            saveToFile(list);
            return;
        }
        q = p;
        p = p->next;
    }
    printf("未找到该职工的信息。\n");
}

// 修改某个职工的信息
void updateEmployee(EmployeeList* list, int id, char* name, char* type, int count) {
    Employee* p = list->head;
    while (p != NULL) {
        if (p->id == id) {
            strcpy(p->name, name);
            strcpy(p->type, type);
            p->count = count;
            saveToFile(list);
            return;
        }
        p = p->next;
    }
    printf("未找到该职工的信息。\n");
}

int main(void) {
    EmployeeList* list = (EmployeeList*) malloc(sizeof(EmployeeList));
    list->head = NULL;
    list->size = 0;
    readFromFile(list);
    int choice = 1;
    while (choice != 0) {
        printf("请选择操作：\n");
        printf("1. 添加职工\n");
        printf("2. 输出职工信息\n");
        printf("3. 对职工按完成数量排序\n");
        printf("4. 统计某个职工的完成数量\n");
        printf("5. 统计某个产品种类的完成数量\n");
        printf("6. 删除某个职工的信息\n");
        printf("7. 修改某个职工的信息\n");
        printf("0. 退出\n");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                addEmployee(list);
                break;
            case 2:
                printEmployees(list);
                break;
            case 3:
                sortEmployees(list);
                printf("排序完成！\n");
                break;
            case 4:
                printf("请输入要统计的职工工号：");
                int id;
                scanf("%d", &id);
                countEmployee(list, id);
                break;
            case 5:
                printf("请输入要统计的产品种类：");
                char type[20];
                scanf("%s", type);
                countType(list, type);
                break;
            case 6:
                printf("请输入要删除的职工工号：");
                int id2;
                scanf("%d", &id2);
                deleteEmployee(list, id2);
                break;
            case 7:
                printf("请输入要修改的职工工号、产品名称、产品种类、完成数量：");
                int id3, count;
                char name[20], type[20];
                scanf("%d %s %s %d", &id3, name, type, &count);
                updateEmployee(list, id3, name, type, count);
                break;
            case 0:
                break;
            default:
                printf("无效的操作！\n");
                break;
        }
    }
    return 0;
}

该程序实现了你所需的各项功能，并且能够将职工信息存储至文件中，支持修改、删除、查询操作。在程序运行时，会提示用户输入操作，并根据用户的选择执行相应的操作。