如何用C语言实现一个简单的模拟银行ATM机器的功能？

在C语言中实现一个简单的银行ATM机模拟，我们可以创建一个类似程序，包含基本的操作函数如存款、取款和查询余额。这里是一个简化的示例：

#include <stdio.h>
#include <stdlib.h> // 用于动态内存分配

// 定义一个结构体表示账户信息
typedef struct {
    int account_number;
    double balance;
} Account;

// 功能函数声明
void deposit(Account* atm, int amount);
double withdraw(Account* atm, int amount);
void check_balance(Account* atm);

int main() {
    Account atm; // 创建一个空的账户
    atm.account_number = 123456; // 设置初始账户号
    atm.balance = 0.0; // 初始化余额为零

    while (1) {
        printf("ATM Menu:\n");
        printf("1. Deposit\n");
        printf("2. Withdraw\n");
        printf("3. Check Balance\n");
        printf("4. Exit\n");
        printf("Enter your choice: ");
        int choice;
        scanf("%d", &choice);

        switch (choice) {
            case 1: deposit(&atm, get_amount_from_user()); break; // 存款函数
            case 2: if (withdraw(&atm, get_amount_from_user())) printf("Withdrawal successful.\n"); else printf("Insufficient funds.\n"); break; // 取款函数
            case 3: check_balance(&atm); break; // 检查余额
            case 4: return 0; // 退出程序
            default: printf("Invalid choice. Please try again.\n");
        }
    }

    return 0;
}

// 辅助函数，从用户获取金额
int get_amount_from_user() {
    int amount;
    printf("Enter the amount: ");
    scanf("%d", &amount);
    return amount;
}

void deposit(Account* atm, int amount) {
    atm->balance += amount;
    printf("Deposited %.2f into account %d. New balance is %.2f.\n", amount, atm->account_number, atm->balance);
}

double withdraw(Account* atm, int amount) {
    if (amount <= atm->balance) {
        atm->balance -= amount;
        return 1; // 表示成功
    } else {
        return 0; // 表示失败
    }
}

void check_balance(Account* atm) {
    printf("Account balance: %.2f.\n", atm->balance);
}