C语言通用性强的链表写一个银行管理系统用文件io多文件

这是一个基本的银行管理系统，使用了C语言中的链表数据结构和文件IO操作，可以实现基本的账户管理、存款、取款和查询等功能。

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

// 定义账户结构体
typedef struct account {
    char name[20]; // 账户名
    char password[20]; // 账户密码
    float balance; // 账户余额
    struct account *next; // 链表指针
} Account;

// 全局变量，指向链表头节点
Account *head = NULL;

// 函数声明
void create_new_account();
void deposit();
void withdraw();
void query();
void save_to_file();
void load_from_file();

int main() {
    int choice;
    while (1) {
        printf("\nWelcome to Bank Management System\n");
        printf("1. Create a new account\n");
        printf("2. Deposit\n");
        printf("3. Withdraw\n");
        printf("4. Query\n");
        printf("5. Exit\n");
        printf("Please enter your choice (1-5): ");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                create_new_account();
                break;
            case 2:
                deposit();
                break;
            case 3:
                withdraw();
                break;
            case 4:
                query();
                break;
            case 5:
                save_to_file();
                printf("Thanks for using Bank Management System. Bye!\n");
                exit(0);
            default:
                printf("Invalid choice. Please try again.\n");
        }
    }
    return 0;
}

// 创建新账户
void create_new_account() {
    Account *new_account = (Account *) malloc(sizeof(Account));
    printf("Please enter the account name: ");
    scanf("%s", new_account->name);
    printf("Please enter the account password: ");
    scanf("%s", new_account->password);
    new_account->balance = 0;
    new_account->next = NULL;

    if (head == NULL) {
        head = new_account;
    } else {
        Account *current = head;
        while (current->next != NULL) {
            current = current->next;
        }
        current->next = new_account;
    }
    printf("Account created successfully.\n");
}

// 存款
void deposit() {
    char name[20], password[20];
    float amount;
    printf("Please enter the account name: ");
    scanf("%s", name);
    printf("Please enter the account password: ");
    scanf("%s", password);
    printf("Please enter the amount to deposit: ");
    scanf("%f", &amount);

    Account *current = head;
    while (current != NULL) {
        if (strcmp(current->name, name) == 0 && strcmp(current->password, password) == 0) {
            current->balance += amount;
            printf("Deposit successful. New balance: %.2f\n", current->balance);
            return;
        }
        current = current->next;
    }
    printf("Account not found or password incorrect.\n");
}

// 取款
void withdraw() {
    char name[20], password[20];
    float amount;
    printf("Please enter the account name: ");
    scanf("%s", name);
    printf("Please enter the account password: ");
    scanf("%s", password);
    printf("Please enter the amount to withdraw: ");
    scanf("%f", &amount);

    Account *current = head;
    while (current != NULL) {
        if (strcmp(current->name, name) == 0 && strcmp(current->password, password) == 0) {
            if (current->balance >= amount) {
                current->balance -= amount;
                printf("Withdrawal successful. New balance: %.2f\n", current->balance);
            } else {
                printf("Insufficient balance.\n");
            }
            return;
        }
        current = current->next;
    }
    printf("Account not found or password incorrect.\n");
}

// 查询账户余额
void query() {
    char name[20], password[20];
    printf("Please enter the account name: ");
    scanf("%s", name);
    printf("Please enter the account password: ");
    scanf("%s", password);

    Account *current = head;
    while (current != NULL) {
        if (strcmp(current->name, name) == 0 && strcmp(current->password, password) == 0) {
            printf("Account balance: %.2f\n", current->balance);
            return;
        }
        current = current->next;
    }
    printf("Account not found or password incorrect.\n");
}

// 将账户信息保存到文件中
void save_to_file() {
    FILE *fp = fopen("accounts.dat", "wb");
    if (fp == NULL) {
        printf("Failed to open file.\n");
        return;
    }

    Account *current = head;
    while (current != NULL) {
        fwrite(current, sizeof(Account), 1, fp);
        current = current->next;
    }
    fclose(fp);
    printf("Accounts saved to file.\n");
}

// 从文件中加载账户信息
void load_from_file() {
    FILE *fp = fopen("accounts.dat", "rb");
    if (fp == NULL) {
        printf("Failed to open file.\n");
        return;
    }

    Account *account = (Account *) malloc(sizeof(Account));
    while (fread(account, sizeof(Account), 1, fp) == 1) {
        account->next = NULL;
        if (head == NULL) {
            head = account;
        } else {
            Account *current = head;
            while (current->next != NULL) {
                current = current->next;
            }
            current->next = account;
        }
        account = (Account *) malloc(sizeof(Account));
    }
    free(account);
    fclose(fp);
    printf("Accounts loaded from file.\n");
}

该程序使用链表来管理账户信息，每个账户包括账户名、密码和余额等信息。程序提供了创建新账户、存款、取款、查询余额等基本功能，并可以将账户信息保存到文件中，以便下次使用时加载。在程序启动时，可以先从文件中加载账户信息，然后在程序结束时将账户信息保存到文件中，以保证数据的持久化。