编写c语言程序:定义员工结构体(员工信息有员工号，员工姓名，部门)。定义一个结构体变量，并使用结构体指针变量对结构体变量赋值，并写入到文件C:\employer.txt文件中。 2.在程序1的基础上，编写函数模块从C:\employer.txt中读取数据并打印输出到屏幕上。

答案：

1. 以下是编写的C语言程序：

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

struct Employee {
    int empNo;
    char empName[50];
    char department[50];
};

int main() {
    struct Employee emp;
    struct Employee *empPtr = &emp;

    printf("Enter employee number: ");
    scanf("%d", &emp.empNo);

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

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

    FILE *fp;
    fp = fopen("C:\\employer.txt", "w");

    if (fp == NULL) {
        printf("Error opening file\n");
        exit(1);
    }

    fprintf(fp, "%d %s %s\n", empPtr->empNo, empPtr->empName, empPtr->department);
    fclose(fp);

    printf("Employee details written to file successfully.\n");

    return 0;
}

2. 以下是从C:\employer.txt中读取数据并打印输出到屏幕上的函数模块：

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

struct Employee {
    int empNo;
    char empName[50];
    char department[50];
};

void printEmployeeDetails() {
    struct Employee emp;
    struct Employee *empPtr = &emp;

    FILE *fp;
    fp = fopen("C:\\employer.txt", "r");

    if (fp == NULL) {
        printf("Error opening file\n");
        exit(1);
    }

    fscanf(fp, "%d %s %s", &empPtr->empNo, empPtr->empName, empPtr->department);
    printf("Employee Number: %d\n", empPtr->empNo);
    printf("Employee Name: %s\n", empPtr->empName);
    printf("Department: %s\n", empPtr->department);

    fclose(fp);
}

int main() {
    printEmployeeDetails();

    return 0;
}