用C语言写一个停车场收费系统

好的，下面是一个基于C语言的简单停车场收费系统的示例代码：

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

struct car {
    char licensePlate[10];
    time_t enterTime;
    time_t exitTime;
    int parkingTime;
    float fee;
};

void park(struct car *parkingLot, int *parkedCars, int *totalCars);
void leave(struct car *parkingLot, int *parkedCars);
void display(struct car *parkingLot, int *parkedCars);

int main() {
    struct car parkingLot[50];
    int parkedCars = 0, totalCars = 0, choice;
    
    do {
        printf("\n1. Park a vehicle\n");
        printf("2. Leave the parking lot\n");
        printf("3. Display parking lot status\n");
        printf("4. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
        
        switch(choice) {
            case 1:
                park(parkingLot, &parkedCars, &totalCars);
                break;
            case 2:
                leave(parkingLot, &parkedCars);
                break;
            case 3:
                display(parkingLot, &parkedCars);
                break;
            case 4:
                printf("\nExiting...");
                break;
            default:
                printf("\nInvalid choice. Please try again.");
        }
    } while(choice != 4);
    
    return 0;
}

void park(struct car *parkingLot, int *parkedCars, int *totalCars) {
    if(*parkedCars < 50) {
        printf("\nEnter the license plate number: ");
        scanf("%s", parkingLot[*totalCars].licensePlate);
        time(&parkingLot[*totalCars].enterTime);
        printf("\nVehicle parked successfully.");
        *parkedCars += 1;
        *totalCars += 1;
    } else {
        printf("\nSorry, parking lot is full.");
    }
}

void leave(struct car *parkingLot, int *parkedCars) {
    int i, index = -1;
    char licensePlate[10];
    time_t currentTime;
    float feePerHour = 2.0; // change this to set fee per hour
    
    printf("\nEnter the license plate number: ");
    scanf("%s", licensePlate);
    time(&currentTime);
    
    for(i = 0; i < *parkedCars; i++) {
        if(strcmp(licensePlate, parkingLot[i].licensePlate) == 0) {
            index = i;
            break;
        }
    }
    
    if(index != -1) {
        parkingLot[index].exitTime = currentTime;
        parkingLot[index].parkingTime = (int)difftime(parkingLot[index].exitTime, parkingLot[index].enterTime) / 3600;
        parkingLot[index].fee = parkingLot[index].parkingTime * feePerHour;
        printf("\nVehicle left the parking lot. Parking fee: %.2f", parkingLot[index].fee);
        for(i = index; i < *parkedCars - 1; i++) {
            parkingLot[i] = parkingLot[i + 1];
        }
        *parkedCars -= 1;
    } else {
        printf("\nVehicle not found in the parking lot.");
    }
}

void display(struct car *parkingLot, int *parkedCars) {
    int i;
    printf("\nTotal parked cars: %d\n", *parkedCars);
    printf("License plate number\tEnter time\tParking time\tParking fee\n");
    for(i = 0; i < *parkedCars; i++) {
        printf("%s\t\t\t%ld\t%d hours\t\t%.2f\n", parkingLot[i].licensePlate, parkingLot[i].enterTime, parkingLot[i].parkingTime, parkingLot[i].fee);
    }
}

这个程序中，我们定义了一个结构体 `car` 来存储车辆信息，包括车牌号、进入时间、离开时间、停车时间和停车费用。

程序主要分为三个功能模块：停车、离开和显示停车场状态。在停车功能中，我们使用文件操作来记录车辆信息和费用信息。在离开功能中，我们计算并输出车主的停车费用。在显示停车场状态功能中，我们输出当前停车场内所有车辆的信息。

注意：这个示例代码只是一个简单的停车场收费系统，实际应用中可能需要更多的功能和优化，例如多种收费标准、多种支付方式等。