链表写学生信息管理系统

链表可以用于实现学生信息管理系统，以下是一个简单的示例代码：

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

// 定义学生结构体
typedef struct student {
    int id; // 学号
    char name[20]; // 姓名
    int age; // 年龄
    struct student *next; // 指向下一个学生的指针
} Student;

// 添加学生信息
void addStudent(Student **head, int id, char *name, int age) {
    Student *newStudent = (Student *)malloc(sizeof(Student));
    newStudent->id = id;
    strcpy(newStudent->name, name);
    newStudent->age = age;
    newStudent->next = NULL;

    if (*head == NULL) {
        *head = newStudent;
    } else {
        Student *temp = *head;
        while (temp->next != NULL) {
            temp = temp->next;
        }
        temp->next = newStudent;
    }
}

// 删除学生信息
void deleteStudent(Student **head, int id) {
    if (*head == NULL) {
        printf("链表为空，无法删除！\n");
        return;
    }

    Student *temp = *head;
    Student *prev = NULL;
    while (temp != NULL) {
        if (temp->id == id) {
            if (prev == NULL) {
                *head = temp->next;
            } else {
                prev->next = temp->next;
            }
            free(temp);
            printf("删除成功！\n");
            return;
        }
        prev = temp;
        temp = temp->next;
    }
    printf("未找到该学生信息！\n");
}

// 修改学生信息
void modifyStudent(Student *head, int id, char *name, int age) {
    if (head == NULL) {
        printf("链表为空，无法修改！\n");
        return;
    }

    Student *temp = head;
    while (temp != NULL) {
        if (temp->id == id) {
            strcpy(temp->name, name);
            temp->age = age;
            printf("修改成功！\n");
            return;
        }
        temp = temp->next;
    }
    printf("未找到该学生信息！\n");
}

// 查找学生信息
void findStudent(Student *head, int id) {
    if (head == NULL) {
        printf("链表为空，无法查找！\n");
        return;
    }

    Student *temp = head;
    while (temp != NULL) {
        if (temp->id == id) {
            printf("学号：%d，姓名：%s，年龄：%d\n", temp->id, temp->name, temp->age);
            return;
        }
        temp = temp->next;
    }
    printf("未找到该学生信息！\n");
}

// 显示所有学生信息
void showAllStudents(Student *head) {
    if (head == NULL) {
        printf("链表为空，无法显示！\n");
        return;
    }

    Student *temp = head;
    while (temp != NULL) {
        printf("学号：%d，姓名：%s，年龄：%d\n", temp->id, temp->name, temp->age);
        temp = temp->next;
    }
}

// 释放链表内存
void freeList(Student **head) {
    Student *temp = *head;
    while (temp != NULL) {
        *head = temp->next;
        free(temp);
        temp = *head;
    }
}

int main() {
    Student *head = NULL;
    int choice, id, age;
    char name[20];

    while (1) {
        printf("请选择操作：\n");
        printf("1.添加学生信息\n");
        printf("2.删除学生信息\n");
        printf("3.修改学生信息\n");
        printf("4.查找学生信息\n");
        printf("5.显示所有学生信息\n");
        printf("6.退出程序\n");
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                printf("请输入学号、姓名、年龄：\n");
                scanf("%d %s %d", &id, name, &age);
                addStudent(&head, id, name, age);
                break;
            case 2:
                printf("请输入要删除的学生学号：\n");
                scanf("%d", &id);
                deleteStudent(&head, id);
                break;
            case 3:
                printf("请输入要修改的学生学号、姓名、年龄：\n");
                scanf("%d %s %d", &id, name, &age);
                modifyStudent(head, id, name, age);
                break;
            case 4:
                printf("请输入要查找的学生学号：\n");
                scanf("%d", &id);
                findStudent(head, id);
                break;
            case 5:
                showAllStudents(head);
                break;
            case 6:
                freeList(&head);
                exit(0);
            default:
                printf("输入有误，请重新输入！\n");
                break;
        }
    }

    return 0;
}