C语言停车场程序栈损坏报错及循环逻辑异常问题咨询

已知问题 #

• 录入第1条车辆信息后无法重新输入车辆类型，对应输入逻辑未按预期循环执行
• 代码修改后触发运行时错误：Run-Time Check Failure #2 - Stack around the variable 'type' was corrupted
• 目标功能为实现支持15个停车位的停车计费全流程管理

原始问题代码 #

float rate(char, int, int);

int main()
{
    int a, b, v, x;
    float r;
    char type;
    printf("\t**\n");
    printf("\t! Welcome to Perdana Parking Management System !\n");
    printf("\t__\n");

printf("\n\tEnter the type of your vehicle (C for car, V for Van) : ");
        scanf("%c", &type);

 
    for (x = 0; x < 15; x++)
    {
        if (type == 'c' || type == 'C' || type == 'v' || type == 'v')
        {
            printf("\n\tEnter vehicle number : ");
            scanf("%d", &v);
            printf("\n");
            printf("\tEnter the Hours Vehicle entered the lot ( from 0 to 24): ");
            scanf("%d", &a);
            printf("\t\n");

            printf("\tEnter the Hours vehicle left the parking lot ( from 0 to 24): ");
            scanf("%d", &b);
            printf("\t\n");

            r = rate(type, a, b);
            printf("\tYour Parking Fee is RM %.2f \n", r);
        }

        else
        {
            printf("\tYou have to Enter the type of your vehicle correctly\n");
            return;
        }
    }

    return 0;
}

float rate(char t, int x, int y)
{
    float rate = 0;
    switch (t)
    {
    case 'C':
    case 'c':if (y - x <= 1)
    {
        rate = 4;
        break;
    }
            else if (y - x > 1 && y - x <= 3)
    {
        rate = ((((y - x) - 1) * 2) + 4);
        break;
    }
            else if (y - x > 3 && y - x <= 24)
    {
        rate = (2 * 2) + (4 * 1) + (((y - x) - 3) * 1);
        break;
    }

    case 'V':
    case'v':if (y - x <= 1)
    {
        rate = 6;
        break;
    }
           else if (y - x > 1 && y - x <= 3)
    {
        rate = ((((y - x) - 1) * 3) + 6);
        break;
    }
           else if (y - x > 3 && y - x <= 24)
    {
        rate = (3 * 2) + (6 * 1) + (((y - x) - 3) * 2);
        break;
    }
    default:
        break;
    }
    return rate;
}

问题根因 #

• 输入位置错误：车辆类型输入语句写在for循环外部，程序启动后仅执行1次，15次循环过程中不会重新触发车辆类型输入，直接导致多车录入流程失效
• 栈损坏诱因：else分支中直接写return;，但main函数定义返回值为int类型，无返回值直接退出会破坏栈帧结构；同时scanf读取字符时未清空输入缓冲区残留的换行符，会出现非预期内存读写，触发栈损坏报错
• 逻辑笔误：车辆类型判断条件重复写了两次type == 'v'，漏掉了大写'V'的判断；rate函数中C类车24小时内计费分支未写break，会穿透执行V类车的计费逻辑，导致费用计算错误

修复后完整代码 #

#include <stdio.h>
// 清空输入缓冲区辅助逻辑
#define CLEAR_BUFFER() while(getchar() != '\n')

float rate(char, int, int);

int main()
{
    int a, b, v, x;
    float r;
    char type;
    printf("\t**\n");
    printf("\t! Welcome to Perdana Parking Management System !\n");
    printf("\t__\n");

    // 15个停车位对应循环15次，车辆类型输入移入循环内部
    for (x = 0; x < 15; x++)
    {
        printf("\n\tEnter the type of your vehicle (C for car, V for Van) : ");
        scanf("%c", &type);
        CLEAR_BUFFER(); // 清空缓冲区残留换行，避免影响后续输入

        // 修正类型判断笔误，覆盖大小写C/V
        if (type == 'c' || type == 'C' || type == 'v' || type == 'V')
        {
            printf("\n\tEnter vehicle number : ");
            scanf("%d", &v);
            CLEAR_BUFFER();
            printf("\n");
            printf("\tEnter the Hours Vehicle entered the lot ( from 0 to 24): ");
            scanf("%d", &a);
            CLEAR_BUFFER();
            printf("\t\n");

            printf("\tEnter the Hours vehicle left the parking lot ( from 0 to 24): ");
            scanf("%d", &b);
            CLEAR_BUFFER();
            printf("\t\n");

            r = rate(type, a, b);
            printf("\tYour Parking Fee is RM %.2f \n", r);
        }
        else
        {
            printf("\tYou have to Enter the type of your vehicle correctly\n");
            // 错误输入不直接退出，跳过当前车位继续下一轮输入
            continue;
        }
    }

    return 0;
}

float rate(char t, int x, int y)
{
    float rate = 0;
    int park_duration = y - x;
    switch (t)
    {
    case 'C':
    case 'c':
        if (park_duration <= 1)
        {
            rate = 4;
        }
        else if (park_duration > 1 && park_duration <= 3)
        {
            rate = (((park_duration - 1) * 2) + 4);
        }
        else if (park_duration > 3 && park_duration <= 24)
        {
            rate = (2 * 2) + (4 * 1) + ((park_duration - 3) * 1);
        }
        break; // 补全break，防止分支穿透
    case 'V':
    case 'v':
        if (park_duration <= 1)
        {
            rate = 6;
        }
        else if (park_duration > 1 && park_duration <= 3)
        {
            rate = (((park_duration - 1) * 3) + 6);
        }
        else if (park_duration > 3 && park_duration <= 24)
        {
            rate = (3 * 2) + (6 * 1) + ((park_duration - 3) * 2);
        }
        break;
    default:
        break;
    }
    return rate;
}

修复说明 #

• 车辆类型输入移入for循环内部，每处理一个车位都会触发一次类型输入，满足15个车位逐车录入的需求
• 增加输入缓冲区清空逻辑，避免残留换行符导致的字符读取异常
• 修正无返回值return的错误写法，输入错误时跳过当前轮次继续循环，不会异常退出也不会破坏栈结构
• 修正类型判断、switch分支穿透的笔误，保证计费逻辑正确

内容的提问来源于stack exchange，提问作者Nurin