停车场代码中的 c 中的奇怪错误，当尝试读取“”之间的字符串时

Question

好吧，基本上你可以通过代码看出，我正在编写一个终端来读取用户给出的命令，其中一个命令是创建停车场的命令“p”，参数为name，容量、cost15（在公园停留15分钟的费用）、cost15_after 1小时（第一个小时后每15分钟的费用）和max_daily_cost。问题是，在命令中输入停车场名称时，当名称之间用空格分隔时，例如 "park number one" ，输入应该在 "" 之间，而当仅给出名称时用一个词来说，例如park1，它不带有“”。这不是我的选择，这是一个大学项目，所以删除“”不是一个选择。然而，奇怪的是，它工作得很好，但前提是我首先输入一个带有单词名称的停车场，然后然后分配一个名称以空格分隔的停车场，因为如果我尝试先分配停车场名字用空格隔开，不行！顺便说一下，单独使用命令 p 不带任何参数，会显示现有的停车场。这是输出：

p "park name" 20 1 2 3
Error: invalid capacity.

p park 20 1 2 3
Parking lot park successfully created!

p "park name" 20 1 2 3
Parking lot park name successfully created!

p
Existing parking lots:
park 20 20
park name 20 20

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define MAXSIZE 100

// Definition of the structure for a parking lot
typedef struct {
    char name[50];
    int capacity;
    float cost15;
    float cost15_after1hour;
    float max_daily_cost;

    int available_spaces;
} ParkingLot;

// Global variable to store the created parking lots
ParkingLot parkingLots[10];
int num_parkingLots = 0;

// Function to create a new parking lot
void createParkingLot(char name[], int capacity, float cost15, float cost15_after1hour, float max_daily_cost) {
    if (num_parkingLots >= 10) {
        printf("Error: too many parking lots.\n");
        return;
    }

    // Check if the parking lot name already exists
    for (int i = 0; i < num_parkingLots; i++) {
        if (strcmp(parkingLots[i].name, name) == 0) {
            printf("Error: %s already exists.\n", name);
            return;
        }
    }

    // Check if the capacity is valid
    if (capacity <= 0) {
        printf("Error: invalid capacity.\n");
        return;
    }

    // Check if the tariff values are increasing
    if (cost15 <= 0 || cost15_after1hour <= cost15 || max_daily_cost <= cost15_after1hour) {
        printf("Error: invalid cost.\n");
        return;
    }

    // Create the new parking lot
    strcpy(parkingLots[num_parkingLots].name, name);
    parkingLots[num_parkingLots].capacity = capacity;
    parkingLots[num_parkingLots].cost15 = cost15;
    parkingLots[num_parkingLots].cost15_after1hour = cost15_after1hour;
    parkingLots[num_parkingLots].max_daily_cost = max_daily_cost;
    parkingLots[num_parkingLots].available_spaces = capacity;
    num_parkingLots++;

    printf("Parking lot %s successfully created!\n", name);
}

// Function to list existing parking lots
void listParkingLots() {
    printf("Existing parking lots:\n");
    for (int i = 0; i < num_parkingLots; i++) {
        printf("%s %d %d\n", parkingLots[i].name, parkingLots[i].capacity, parkingLots[i].available_spaces);
    }
}

int main() {
    char command[20];
    char name[50];
    int capacity;
    float cost15, cost15_after1hour, max_daily_cost;

   
    printf("p [ <park-name> <capacity> <cost-15> <cost-15-after-1hour> <max-daily-cost> ] - Create parking lot\n");
    
    
    while (1) {
        
        scanf("%s", command);
        

        if (strcmp(command, "p") == 0) {
            char nextChar = getchar(); // Reads the next character after the "p"
            if (nextChar == '\n') {
                listParkingLots();
            } else {
                ungetc(nextChar, stdin); // Returns the unread character to the buffer
                char str[MAXSIZE];
                fgets(str, MAXSIZE, stdin);
                char *p = strchr(str, '\"');

                if (p){
                    char str_between_quotes[MAXSIZE];
                    int i = 0;
                    p++; // Moves the pointer to the next character after the first quote
                    while (*p != '\"' && *p != '\n' && *p != '\0') {
                        str_between_quotes[i] = *p;
                        i++;
                        p++;
                    }
                    str_between_quotes[i] = '\0'; // Ends the string
                    strcpy(name,str_between_quotes);
                } else {
                    sscanf(str, "%s %d %f %f %f", name, &capacity, &cost15, &cost15_after1hour, &max_daily_cost);
                }
                createParkingLot(name,capacity,cost15,cost15_after1hour,max_daily_cost);
            }
        } else if (strcmp(command, "q") == 0) {
            break;
        } else {
            printf("Invalid command.\n");
        }
    }

    return 0;
}

我尝试使用linux中的gdb工具对其进行调试，但没有得出结论。我认为这可能与指针或其他东西有关，我还不是真正的 C 大师。我也很欣赏这段代码的一些提示，有没有更好的方法来完成我想做的事情？希望有人可以帮助我，谢谢

Answer 1

在这个 if 语句中

if (p){
    char str_between_quotes[MAXSIZE];
    int i = 0;
    p++; // Moves the pointer to the next character after the first quote
    while (*p != '\"' && *p != '\n' && *p != '\0') {
        str_between_quotes[i] = *p;
        i++;
        p++;
    }
    str_between_quotes[i] = '\0'; // Ends the string
    strcpy(name,str_between_quotes);
} 

您忘记提取这些项目：capacity、cost15、cost15_after1hour、max_daily_cost。因此它们具有不确定的值，或者这个 if 语句是第一个在 while 循环中获得输入控制权的语句。