c - 我正在尝试用 C 语言制作一个菜单，但我的代码没有按照我想要的方式工作

Question

我正在为我的编程课做作业，我处理的第一件事当然是制作主菜单。但出于某种原因，该程序没有按我预期的方式运行。

#include <stdio.h>
#include <stdlib.h>
void mainMenu();
void firstChoice();
int main()
{
    int main_menu_choice;
    int _1returnMenu;
    mainMenu();
    scanf("%d", &main_menu_choice);
    while (main_menu_choice != 0){
        switch(main_menu_choice){
        case 1:
        firstChoice();
        scanf("%d", &_1returnMenu);
        while (_1returnMenu != 0){
            switch (_1returnMenu){
            case 1:
            firstChoice();
            scanf("%d", &_1returnMenu);
            break;
            case 0:
            mainMenu();
            scanf("%d", &main_menu_choice);
            break;
            default:
            printf("Invalid option, please try again: \n");
            scanf("%d", &_1returnMenu);
            break;
            }
        }
        break;
        case 0:
        exit(0);
        default:
        printf("Invalid option, please try again: \n");
        scanf("%d", &main_menu_choice);
        }
    }
    return 0;
}

void firstChoice(){
    printf("Enter the necessary information \n");
    printf("Please enter the student's ID: \n");
    scanf("%d", &student.id);
    printf("Please enter the student's name: \n");
    scanf("%s", student.name);
    printf("Please enter the gender of the student: \n");
    scanf("%s", student.gender);
    printf("Please enter the details of the room: \n");
    scanf("%s", student.roomDetails);
    printf("Please enter the amount due of the student: \n");
    scanf("%d", &student.amountDue);
    printf("Please enter the amount paid by the student: \n");
    scanf("%d", &student.paymentMade);
    printf("Do you want to store another hosteler's information? \n");
    printf("Type 1 if you wish to continue, Type 0 to go back to the main menu: \n");
    return;
}

void mainMenu(){
    printf("Welcome! This program will help you in managing the hostel booking 
    of Wisdom College \n");
    printf("Type the number of your option: \n");
    printf("1. Store details of hosteler \n");
    printf("2. Check room availability \n");
    printf("3. Payment Facility \n");
    printf("4. Search room details of hosteler \n");
    printf("5. To cancel booking of a hosteler \n");
    printf("6. Change room type \n");
    printf("0. Exit the program \n");
    return;
}

好的，当我运行程序并选择第一个选项“1.Store details of hosteler”时，只需输入一些随机信息，在输入所需信息后，程序会询问我是否要继续使用它与否。如果我按 1，它会要求我再次填写所需信息，如果我按 0，它应该返回主菜单。 但问题是，当我输入 0 时，它不会返回主菜单，而是再次运行 firstChoice() 函数，而不是在 switch 语句中运行 case 0。我一直在挠头 2 个小时，试图找出问题所在，但我似乎无法找到问题所在。如果我无法正确表达我的问题，我感到非常抱歉，在此先感谢您!

Answer 1

下面建议的代码显示了如何编写菜单显示和处理

int done = 0;
while( !done )
{
    mainMenu();
    if( scanf("%d", &main_menu_choice) != 1 )
    {
        fprintf( stderr, "scanf for menu choice failed\n" );
        exit( EXIT_FAILURE );
    }

    switch(main_menu_choice)
    {

    case 0:
        done = 1;
        break;

    case 1:
        firstChoice();
        break;

    case 2:
        checkRoomAvalability();
        break;

    case 3:
        paymentFacility();
        break;

    case 4:
        switchRoomDetails();
        break;

    case 5:
        cancelBooking();
        break;

    case 6:
        changeRoomType();
        break;         

    default:
        puts("Invalid option, please try again: \n");
        break;
    }
}


void mainMenu()
{
    puts(  "Welcome!"
           " This program will help you in managing"
           " the hostel booking of Wisdom College \n"
           "Type the number of your option: \n"
           "1. Store details of hosteler \n"
           "2. Check room availability \n"
           "3. Payment Facility \n"
           "4. Search room details of hosteler \n"
           "5. To cancel booking of a hosteler \n"
           "6. Change room type \n"
           "0. Exit the program \n" );
}