function ran even though it's not called

[Lema]

Hello everyone,im creating a program to input product that asks for itemName,size,amount,and hour+minute
everything so far looks good, but when i compile and chose menu "1" which is adding item by pushing the data inputted, it ran del() function even though i havent called it yet and cout<<w<<"--- Add New Order Success ---"; didnt show up

also, when i chose menu "2", it successfully printed "no data available" but didnt return to mainMenu after pressing "enter" key

feel free to point anything im doing wrong ,and i'm using doubly linked list with push pop method in C because i dont quite understand using vector which the data are encapsulated in classes

#include<iostream>
#include<string>
#include<iomanip>
using namespace std;
#define w setw(2)<<flag<<"|"
#define f flag++
#define s cin.sync();cin.clear()
static int flag;

class receiveDate{
public:
    int hour;
    int minute;
};

class item:public receiveDate{
public:
    int jumlah;
    char namaProduk[20];
    int ukuran;
    class item *prev,*next;
};
class item *head=NULL,*curr,*tail;

void clear(){
    int i;
    for(i=0;i<100;i++){
        cout<<endl;
    }
}

void header(){
    clear();
    int a = 1;
    cout<<"           ";
    for(int i=0;i<=90;i++){
        int b = i%10;
        if(b==0){
            cout<<a;
            a++;
        }else{
            cout<<" ";
        }
    }
    cout<<endl<<"  ";
    for(int i = 0;i<=9;i++){
        printf("1234567890");
    }
    cout<<endl<<"  ";
    for(int i=0;i<=100;i++){
        printf("=");
    }
    cout<<endl;
}

void pop(){
    class item *temp;

    if(head!=NULL){
        if(curr == head)
        {
            head = head->next;
            free(curr);
            if(head != NULL)
            {
                head->prev = NULL;
            }
        }
        else if(curr == tail)
        {
            curr = tail;
            tail = tail->prev;
            free(curr);
            tail->next = NULL;
        }
        else
        {
            temp = head;
            while(temp->next != curr)
            {
                temp = temp->next;
            }
            curr->next->prev = curr->prev;
            temp->next = curr->next;
            free(curr);
        }
    }
}

void popall()
{
    while(head!=NULL)
    {
        curr=head;
        head=head->next;
        free(curr);
    }
}

void display(){
    header();
    int i=0;
    curr=head;
    cout<<w<<setw(22)<<"Item Name"<<setw(8)<<"Ukuran"<<setw(4)<<"Jam Pesan"<<endl;f;
    while(curr){
        i++;
        cout<< w << setw(2) << i <<setw(20) << curr->namaProduk << setw(8)<<curr->ukuran <<setw(4) << curr->hour << ":" << curr->minute;f;
        curr=curr->next;
    }
}
void push(char namaProduk[],int ukuran,int jumlah,int hour,int minute){
    curr=(class item*)malloc(sizeof(class item));
    class item *temp;
    strcpy(curr->namaProduk,namaProduk);
    curr->jumlah=jumlah;
    curr->ukuran=ukuran;
    curr->hour=hour;
    curr->minute=minute;
    if(head==NULL){
        head=tail=curr;
    }else{
        curr->next=head;
        head->prev=curr;
        head=curr;
    }
    head->prev=NULL;
    tail->next=NULL;
}
void add(){
    header();
    flag=1;
    char namaProduk[20];
    int ukuran;
    int jumlah;
    int hour;
    int minute;
    char jenis[10];
    do{
        cout<<w<<"Input nama produk [3-30] : ";f;
        cin>>namaProduk;s;
    }while(strlen(namaProduk)<3 || strlen(namaProduk)>30);
    do{
        cout<<w<<"Input ukuran [1 = kecil, 2 = sedang, 3 = besar] : ";f;
        cin>>ukuran;s;
    }while(ukuran<1||ukuran>3);
    do{
        cout<<w<<"Jumlah item [1 - 999] : ";f;
        cin>>jumlah;s;
    }while(jumlah<1||jumlah>999);
    do{
        cout<<w<<"Jam pesan :";f;
        cin>>hour;s;
    }while(hour<0||hour>24);
    do{
        cout<<w<<"Menit pesan:";f;
        cin>>minute;s;
    }while(minute<0||minute>59);
    push(namaProduk,ukuran,jumlah,hour,minute);

    cout<<w<<"--- Add New Order Success ---";
    cin.get();
}

void del(){
    int tot = 0;
    int pos;
    int qty;
    int i;
    if(head==NULL)
    {
        cout<<"--- There is No Order in The List ---";
    }
    else
    {
        curr = head;
        while(curr)
        {
            tot++;
            curr = curr->next;
        }
        display();
        do
        {
            cout<<" Input Number of The Order [1.."<< tot<<"]";
            cin>>pos;s;
        }while(pos<1 || pos>tot);
        
        curr = head;

        for(i=1;i<pos;i++)
        {
            curr = curr->next;
        }
        pop();

        cout<<endl<<" --- Take Order Success ---";
        cin.get();
    }
}

void menu(){
    int menu;
    header();
    flag=1;
    cout<<w<<endl;f;
    cout<<w<<endl;f;
    cout<<w<<endl;f;
    cout<<w<<setw(57)<<"PROGRAM INVENTARIS MINIMARKET"<<endl;f;
    cout<<w<<setw(58)<<"=============================="<<endl;f;
    cout<<w<<"     Pilih Menu:"<<endl;f;
    cout<<w<<"      1. Add Item"<<endl;f;
    cout<<w<<"      2. View Inventory"<<endl;f;
    cout<<w<<"      3. Remove order"<<endl;f;
    cout<<w<<"      4. Remove all order"<<endl;f;
    cout<<w<<"      5. Exit Program"<<endl;f;
    cout<<w<<"      Input Menu: ";f;
    cin>>menu;s;
    cin.sync();cin.clear();
    switch(menu){
    case 1:
        add();
    case 2:
        display();
    case 3:
        del();
    case 4:
        popall();
    }while(menu!=5);
}
int main()
{   
    menu();
    return 0;
}

[Lema]

im kinda stuck because i don't know what to fix
it doesnt show any error

[Peter87]

Switch statements are a bit primitive. If you don't use a break statement it will just go on executing the code in the other cases that comes after.

switch (menu) {
case 1:
	add();
	break;
case 2:
	display();
	break;
case 3:
	del();
	break;
case 4:
	popall();
	break;
}