写一个银行自动ATM机存取系统的C语言代码要求a) 开户 b) 账户登录 c)密码修改 a) 存款 b) 取款 c) 转账 d) 余额查询

以下是一个包含开户、账户登录、密码修改、存款、取款、转账、余额查询功能的银行自动ATM机存取系统的C语言代码示例：

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

#define MAX_ACCOUNTS 10
#define MAX_NAME_LEN 20
#define MAX_PASS_LEN 10

struct account {
    int id;
    char name[MAX_NAME_LEN];
    char password[MAX_PASS_LEN];
    int balance;
};

struct account accounts[MAX_ACCOUNTS];
int num_accounts = 0;

int current_account = -1;

void create_account() {
    if (num_accounts >= MAX_ACCOUNTS) {
        printf("对不起，系统最多只能支持 %d 个账户\n", MAX_ACCOUNTS);
        return;
    }

    struct account new_account;
    new_account.id = num_accounts + 1;

    printf("请输入姓名：\n");
    scanf("%s", new_account.name);

    printf("请输入密码：\n");
    scanf("%s", new_account.password);

    new_account.balance = 0;

    accounts[num_accounts] = new_account;
    num_accounts++;

    printf("账户创建成功，您的账户ID为：%d\n", new_account.id);
}

void login() {
    char name[MAX_NAME_LEN];
    char password[MAX_PASS_LEN];

    printf("请输入账户名：\n");
    scanf("%s", name);

    printf("请输入密码：\n");
    scanf("%s", password);

    for (int i = 0; i < num_accounts; i++) {
        if (strcmp(accounts[i].name, name) == 0 && strcmp(accounts[i].password, password) == 0) {
            current_account = i;
            printf("登录成功，欢迎回来，%s！\n", accounts[i].name);
            return;
        }
    }

    printf("账户名或密码错误，请重新输入\n");
}

void change_password() {
    if (current_account == -1) {
        printf("请先登录\n");
        return;
    }

    char old_password[MAX_PASS_LEN];
    char new_password[MAX_PASS_LEN];

    printf("请输入旧密码：\n");
    scanf("%s", old_password);

    if (strcmp(accounts[current_account].password, old_password) != 0) {
        printf("旧密码不正确，请重新输入\n");
        return;
    }

    printf("请输入新密码：\n");
    scanf("%s", new_password);

    strcpy(accounts[current_account].password, new_password);

    printf("密码修改成功\n");
}

void deposit() {
    if (current_account == -1) {
        printf("请先登录\n");
        return;
    }

    int amount;

    printf("请输入存款金额：\n");
    scanf("%d", &amount);

    accounts[current_account].balance += amount;

    printf("存款成功，当前余额为：%d元\n", accounts[current_account].balance);
}

void withdraw() {
    if (current_account == -1) {
        printf("请先登录\n");
        return;
    }

    int amount;

    printf("请输入取款金额：\n");
    scanf("%d", &amount);

    if (amount > accounts[current_account].balance) {
        printf("余额不足，取款失败\n");
        return;
    }

    accounts[current_account].balance -= amount;

    printf("取款成功，当前余额为：%d元\n", accounts[current_account].balance);
}

void transfer() {
    if (current_account == -1) {
        printf("请先登录\n");
        return;
    }

    int target_id, amount;

    printf("请输入转账目标账户ID：\n");
    scanf("%d", &target_id);

    if (target_id <= 0 || target_id > num_accounts) {
        printf("目标账户不存在，请重新输入\n");
        return;
    }

    if (target_id == accounts[current_account].id) {
        printf("不能向自己转账，请重新输入\n");
        return;
    }

    printf("请输入转账金额：\n");
    scanf("%d", &amount);

    if (amount > accounts[current_account].balance) {
        printf("余额不足，转账失败\n");
        return;
    }

    accounts[current_account].balance -= amount;
    accounts[target_id - 1].balance += amount;

    printf("转账成功，当前余额为：%d元\n", accounts[current_account].balance);
}

void check_balance() {
    if (current_account == -1) {
        printf("请先登录\n");
        return;
    }

    printf("当前余额为：%d元\n", accounts[current_account].balance);
}

int main() {
    int choice;

    while (1) { // 不断循环，直到用户选择退出
        printf("\n欢迎使用银行ATM机\n");

        if (current_account == -1) {
            printf("请选择操作：\n");
            printf("1. 开户\n");
            printf("2. 登录\n");
        } else {
            printf("请选择操作：\n");
            printf("1. 修改密码\n");
            printf("2. 存款\n");
            printf("3. 取款\n");
            printf("4. 转账\n");
            printf("5. 余额查询\n");
            printf("6. 注销\n");
        }

        scanf("%d", &choice);

        switch (choice) {
            case 1:
                create_account();
                break;
            case 2:
                login();
                break;
            case 3:
                if (current_account == -1) {
                    printf("请先登录\n");
                } else {
                    change_password();
                }
                break;
            case 4:
                if (current_account == -1) {
                    printf("请先登录\n");
                } else {
                    deposit();
                }
                break;
            case 5:
                if (current_account == -1) {
                    printf("请先登录\n");
                } else {
                    withdraw();
                }
                break;
            case 6:
                if (current_account == -1) {
                    printf("请先登录\n");
                } else {
                    transfer();
                }
                break;
            case 7:
                if (current_account == -1) {
                    printf("请先登录\n");
                } else {
                    check_balance();
                }
                break;
            case 8:
                if (current_account == -1) {
                    printf("欢迎下次再来！\n");
                } else {
                    printf("注销成功，欢迎下次再来！\n");
                    current_account = -1;
                }
                return 0;
            default:
                printf("无效的选择，请重新选择\n");
                break;
        }
    }
}

该代码在上一个示例的基础上增加了开户、账户登录、密码修改、转账等多个功能。在开户功能中，程序会检查账户数量是否超过上限，并让用户输入姓名和密码，然后分配一个新的账户ID。在登录功能中，程序会让用户输入账户名和密码，然后检查是否有对应的账户。在密码修改、存款、取款、转账、余额查询等功能中，程序会先检查用户是否已经登录，然后根据用户的选择执行相应的操作。如果用户选择了注销操作，程序会结束运行。