sahapersian sahapersian - 1 year ago 64
C++ Question

Auto generate ID in C++

// AnE.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include<conio.h>
#include<string.h>
#include<stdlib.h>
#include<iostream>
using namespace std;


// The maximum number of patients in queue
#define MAXPATIENTS 30


// define structure for patient information
struct patient

{
char FirstName[50];
char LastName[50];
char ID[20];
};


// define class for queue
class queue
{
public:
queue (void);
int RegisterPatien (patient p);
int RegisterPatientAtBeginning (patient p);
patient GetNextPatient (void);
int CancelAll (patient * p);
void OutputList (void);
char DepartmentName[50];
private:
int ShowAllPatient;
patient List[MAXPATIENTS];
};


// declare member functions for queue

queue::queue ()
{
// Constructor
ShowAllPatient = 0;
}


int queue::RegisterPatien (patient p)
{
// To add a patient (normally) to the queue (to the end).
// returns 1 if successful, 0 if queue is full.
if (ShowAllPatient >= MAXPATIENTS)
{
// queue is full
return 0;
}
// put in new patient
else
List[ShowAllPatient] = p; ShowAllPatient++;
return 1;
}


int queue::RegisterPatientAtBeginning (patient p)
{
// adds a critically ill patient to the beginning of the queue.
// returns 1 if successful, 0 if queue is full.
int i;
if (ShowAllPatient >= MAXPATIENTS)
{
// queue is full
return 0;
}

// move all patients one position back in queue
for (i = ShowAllPatient-1; i >= 0; i--)
{
List[i+1] = List[i];
}
// put in new patient
List[0] = p; ShowAllPatient++;
return 1;
}


patient queue::GetNextPatient (void)
{
// gets the patient that is first in the queue.
// returns patient with no ID if queue is empty

int i; patient p;
if (ShowAllPatient == 0) {
// queue is empty
strcpy(p.ID,"");
return p;}
// get first patient
p = List[0];
// move all remaining patients one position forward in queue
ShowAllPatient--;
for (i=0; i<ShowAllPatient; i++)
{
List[i] = List[i+1];
}
// return patient
return p;
}


int queue::CancelAll (patient * p)

{
// removes a patient from queue.
// returns 1 if successful, 0 if patient not found
int i, j, found = 0;
// search for patient
for (i=0; i<ShowAllPatient; i++)
{
if (stricmp(List[i].ID, p->ID) == 0)
{
// patient found in queue
*p = List[i]; found = 1;
// move all following patients one position forward in queue
ShowAllPatient--;

for (j=i; j<ShowAllPatient; j++)
{
List[j] = List[j+1];
}
}
}
return found;
}


void queue::OutputList (void)
{
// lists entire queue on screen
int i;
if (ShowAllPatient == 0)
{
cout<< "Queue is empty";
}
else
{

for (i=0; i<ShowAllPatient; i++)
{
cout << "First Name : " << List[i].FirstName<<endl;
cout << "Last Name : " << List[i].LastName<<endl;
}
}
}


// declare functions used by main:

patient InputPatient (void)

{
// this function asks user for patient data.
patient p;
cout<<endl<<endl;
cout << "Please enter the information of the Patient"<<endl<<endl;
cout << "First name: "<<endl<<endl;
cin.getline(p.FirstName, sizeof(p.FirstName));
cout << "Last name: "<<endl<<endl;
cin.getline(p.LastName, sizeof(p.LastName));
// check if data valid
if (p.FirstName[0]==0 || p.LastName[0]==0 || p.ID[0]==0)
{
// rejected
strcpy(p.ID,"");
cout << "Error: Data not valid. Operation cancelled.";
getch();
}
return p;
}


void OutputPatient (patient * p)
{
// this function outputs patient data to the screen
if (p == NULL || p->ID[0]==0)
{
cout << "No patient";

return;
}
else
cout << "Patient Information:"<<endl<<endl;
cout << "First name: " << p->FirstName<<endl<<endl;
cout << "Last name: " << p->LastName<<endl<<endl;
}


int ReadNumber()
{
// this function reads an integer number from the keyboard.
// it is used because input with cin >> doesn't work properly!
char buffer[20];
cin.getline(buffer, sizeof(buffer));
return atoi(buffer);
}


void DepartmentMenu (queue * q)
{
// this function defines the user interface with menu for one department
int choice = 0, success; patient p;
while (choice != 6)
{
// print menu
system("CLS");
cout << "<< || Welcome || >> "<<endl << q->DepartmentName<<endl;
cout << "Please enter your choice:"<<endl<<endl;
cout << "1: Register patient"<<endl;
cout << "2: Serve patient "<<endl;
cout << "3: Cancel all patients from queue"<<endl;
cout << "4: Show all patient"<<endl;
cout << "5: Exit"<<endl<<endl<<endl<<endl<<endl<<endl<<endl<<endl;

choice = ReadNumber();

switch (choice)
{
case 1: // Add new patient
p = InputPatient();
if (p.ID[0])
{
success = q->RegisterPatien(p);
system("CLS");
if (success)
{
cout << "Patient added:"<<endl<<endl;

}
else
{
// error
cout << "Sorry: The queue is full. We Cannot add any patient:";
}
OutputPatient(&p);
cout << "Press any key";
getch();
}
break;

case 2: // Call patient for operation /First Come First Surve
p = q->GetNextPatient();
system("CLS");
if (p.ID[0])
{
cout << "Patient to operate:";
OutputPatient(&p);
}
else
{
cout << "Currently there is no patient to operate.";
}
cout << "Press any key to contiune";
getch();
break;

case 3: // Cancel all from queue
p = InputPatient();
if (p.ID[0])
{
success = q->CancelAll(&p);
system("CLS");
if (success)
{
cout << "Patient removed:";
}
else
{
// error
cout << "Sort: We cannot find patient:";
}
OutputPatient(&p);
cout << "Press any key to contiune";
getch();
}
break;

case 4: // Show all patient -> queues
system("CLS");
q->OutputList();
cout << "Press any key";
getch(); break;
}
}
}


// the main function defining queues and main menu
void main ()
{
int i, MenuChoice = 0;
// define queue
queue department[1];
// set department name
strcpy_s (department[0].DepartmentName, "To Emergency Department");

while (MenuChoice != 2)
{
system("CLS");

// Cout menu
cout<<"\n------------------------------------\n";
cout << "Welcome to Waiting Room Management System"<<endl;
cout<<"---------------------------------------\n";
cout << "Please Select a Number from the following menu:"<<endl<<endl;
for (i = 0; i < 1; i++)

{
// write menu item for department i
cout<< "" << (i+1) << ": "<< department[i].DepartmentName;
cout<<endl;
}
cout << "2: Exit"<<endl;
// get user choice
MenuChoice = ReadNumber();
// is it a department name?
if (MenuChoice >= 1 && MenuChoice <= 1)
{
// call submenu for department
// (using pointer arithmetics here:)
DepartmentMenu (department + (MenuChoice-1));
}
}
}


Okay, it's Vc++ for waiting room. You can see the code is working well, but I have problem with generating ID! I need to generate ID for each patient (auto-generate by system). How I can generate ID for my queue?
Thanks alot !

Answer Source

Usually, you'd do it by putting a static variable in that class, and each time you get a new patient, you assign its current value to the current patient, then increment it.

class patient { 
    // ...
    int id;

    static int current_id; // added

    patient() : id(current_id++) {} // added
};

int patient::current_id; // added
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