C语言实战2

C语言实战案例：文件操作与数据结构

案例目标：
实现一个学生信息管理系统，包含文件读写、链表操作和基本增删改查功能。

文件读写与链表结合

定义学生结构体并创建链表：

typedef struct Student { int id; char name[50]; float score; struct Student *next; } Student;

文件写入函数示例：

void saveToFile(Student *head, const char *filename) { FILE *file = fopen(filename, "w"); if (!file) return; Student *current = head; while (current != NULL) { fprintf(file, "%d %s %.2f\n", current->id, current->name, current->score); current = current->next; } fclose(file); }

动态内存管理

从文件加载数据到链表：

Student* loadFromFile(const char *filename) { FILE *file = fopen(filename, "r"); if (!file) return NULL; Student *head = NULL, *tail = NULL; while (!feof(file)) { Student *newNode = (Student*)malloc(sizeof(Student)); if (fscanf(file, "%d %s %f", &newNode->id, newNode->name, &newNode->score) == 3) { newNode->next = NULL; if (!head) head = newNode; else tail->next = newNode; tail = newNode; } else { free(newNode); break; } } fclose(file); return head; }

实用功能实现

链表插入与删除操作：

void insertStudent(Student **head, int id, const char *name, float score) { Student *newNode = (Student*)malloc(sizeof(Student)); newNode->id = id; strcpy(newNode->name, name); newNode->score = score; newNode->next = *head; *head = newNode; } void deleteStudent(Student **head, int id) { Student *temp = *head, *prev = NULL; while (temp != NULL && temp->id != id) { prev = temp; temp = temp->next; } if (temp == NULL) return; if (prev == NULL) *head = temp->next; else prev->next = temp->next; free(temp); }

高级应用示例

排序功能实现（冒泡排序）：

void sortByScore(Student **head) { if (!*head || !(*head)->next) return; int swapped; Student *ptr1; Student *lptr = NULL; do { swapped = 0; ptr1 = *head; while (ptr1->next != lptr) { if (ptr1->score < ptr1->next->score) { // 交换数据域 Student temp = *ptr1; ptr1->id = ptr1->next->id; strcpy(ptr1->name, ptr1->next->name); ptr1->score = ptr1->next->score; ptr1->next->id = temp.id; strcpy(ptr1->next->name, temp.name); ptr1->next->score = temp.score; swapped = 1; } ptr1 = ptr1->next; } lptr = ptr1; } while (swapped); }

错误处理增强

增加文件操作安全检查：

Student* safeLoad(const char *filename) { FILE *file = fopen(filename, "r"); if (!file) { perror("Error opening file"); return NULL; } // ...（其余加载逻辑） if (ferror(file)) { perror("Error reading file"); clearerr(file); fclose(file); return NULL; } fclose(file); return head; }

该案例完整实现了文件持久化存储、动态内存管理、链表操作等核心功能，可作为C语言中级练习的典型范例。实际开发时可进一步扩展搜索功能、界面交互等模块。