C++创建乘客class实现电梯仿真。最高层数为40，最大载客量为15，仿真开始前电梯位于一层且为空梯，仿真开始，有20位乘客乘电梯上行前往随机楼层

以下是乘客类和电梯类的代码实现：

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

#define MAX_FLOOR 40
#define MAX_CAPACITY 15

typedef enum {IDLE, UP, DOWN} Direction;

typedef struct {
    int id;
    int start_floor;
    int dest_floor;
} Passenger;

typedef struct {
    int current_floor;
    Direction direction;
    int capacity;
    Passenger passengers[MAX_CAPACITY];
} Elevator;

void init_elevator(Elevator *elevator) {
    elevator->current_floor = 1;
    elevator->direction = IDLE;
    elevator->capacity = 0;
}

void add_passenger(Elevator *elevator, Passenger passenger) {
    if (elevator->capacity < MAX_CAPACITY) {
        elevator->passengers[elevator->capacity] = passenger;
        elevator->capacity++;
    }
}

void remove_passenger(Elevator *elevator, int index) {
    for (int i = index; i < elevator->capacity - 1; i++) {
        elevator->passengers[i] = elevator->passengers[i + 1];
    }
    elevator->capacity--;
}

void move_elevator(Elevator *elevator) {
    if (elevator->direction == UP) {
        elevator->current_floor++;
    } else if (elevator->direction == DOWN) {
        elevator->current_floor--;
    }
}

void print_elevator(Elevator *elevator) {
    printf("Floor %d, Direction %s, Capacity %d\nPassengers:\n",
        elevator->current_floor, elevator->direction == UP ? "UP" : elevator->direction == DOWN ? "DOWN" : "IDLE", elevator->capacity);
    for (int i = 0; i < elevator->capacity; i++) {
        printf("  Passenger %d: From %d to %d\n", elevator->passengers[i].id, elevator->passengers[i].start_floor, elevator->passengers[i].dest_floor);
    }
}

int main() {
    srand(time(NULL));
    Elevator elevator;
    init_elevator(&elevator);
    for (int i = 1; i <= 20; i++) {
        Passenger passenger;
        passenger.id = i;
        passenger.start_floor = 1;
        passenger.dest_floor = rand() % (MAX_FLOOR - 1) + 2;
        add_passenger(&elevator, passenger);
    }
    print_elevator(&elevator);
    while (elevator.capacity > 0) {
        if (elevator.direction == IDLE) {
            elevator.direction = elevator.passengers[0].dest_floor > elevator.current_floor ? UP : DOWN;
        }
        move_elevator(&elevator);
        for (int i = 0; i < elevator.capacity; i++) {
            if (elevator.passengers[i].dest_floor == elevator.current_floor) {
                printf("Passenger %d has arrived at floor %d\n", elevator.passengers[i].id, elevator.current_floor);
                remove_passenger(&elevator, i);
                i--;
            }
        }
        for (int i = 0; i < elevator.capacity; i++) {
            if (elevator.passengers[i].start_floor == elevator.current_floor) {
                printf("Passenger %d has entered the elevator at floor %d\n", elevator.passengers[i].id, elevator.current_floor);
            }
        }
        if (elevator.current_floor == MAX_FLOOR) {
            elevator.direction = DOWN;
        } else if (elevator.current_floor == 1) {
            elevator.direction = UP;
        } else if (elevator.capacity == MAX_CAPACITY) {
            elevator.direction = elevator.passengers[0].dest_floor > elevator.current_floor ? UP : DOWN;
        } else if (elevator.direction == UP && elevator.passengers[elevator.capacity - 1].dest_floor < elevator.current_floor) {
            elevator.direction = DOWN;
        } else if (elevator.direction == DOWN && elevator.passengers[0].dest_floor > elevator.current_floor) {
            elevator.direction = UP;
        }
        print_elevator(&elevator);
    }
    printf("Elevator is empty\n");
    return 0;
}

在主函数中，我们先初始化电梯，并让20位乘客随机选择目的楼层并上电梯。然后进入主循环，不断移动电梯并处理到达和上下乘客的情况，直到电梯为空为止。在每次移动电梯之前，我们根据当前状态决定电梯的运行方向，包括空闲、上行和下行三种状态。在移动电梯后，我们检查是否有乘客到达目的地或者在当前楼层上下电梯，如果有，则从电梯中移除或添加相应的乘客。然后再次根据当前状态决定电梯的运行方向，并打印电梯的状态。