reservation system

this system we need to key in bus records...before doin reservation...
now...how to modify this program to set buses already available...n user can book the ticket directly...

Code:

#include <conio.h>
#include <stdio.h>
#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <dos.h>

using namespace std;

static int p=0;
class a
{
		char busn[5],driver[10],arrival[5],depart[5],from[10],to[10],
		seat[8][4][10];
	public:
		void install();
		void allotment();
		void empty();
		void show();
		void avail();
		void position(int i);
}bus[10];//here we declare the number of buses we can have.
void vline(char ch)
{
	for (int i=80;i>0;i--)//Here i's value will depend on your computer.
		cout<<ch;
}
void a::install()
{
	cout<<"Enter bus no: ";
	cin>>bus[p].busn;
	cout<<"\n Enter Driver's name: ";
	cin>>bus[p].driver;
	cout<<"\n Arrival time: ";
	cin>>bus[p].arrival;
	cout<<"\n Departure: ";
	cin>>bus[p].depart;
	cout<<"\n From: \t\t\t";
	cin>>bus[p].from;
	cout<<"\n To: \t\t\t";
	cin>>bus[p].to;
	bus[p].empty();
	p++;
}
void a::allotment()
{
	int seat;
	char number[5];
	top:
	cout<<"Bus no: ";
	cin>>number;
	int n;
	for(n=0;n<=p;n++)
	{
		if(strcmp(bus[n].busn,number)==0)
		break;
	}
	while(n<=p)
	{
		cout<<"\n Seat number: ";
		cin>>seat;
		if (seat>32)
			{
				cout<<"\n There are only 32 seats available in this bus.";
			}
		else
			{
			if (strcmp(bus[n].seat[seat/4][(seat%4)-1],"Empty")==0)
				{
					cout<<"Enter passanger's name: ";
					cin>>bus[n].seat[seat/4][(seat%4)-1];
					break;
				}
			else
				cout<<"The seat no. is already reserved.\n";
			}
	}
	if (n>p)
	{
		cout<<"Enter correct bus no.\n";
		goto top;
	}
}
void a::empty()
{
	for(int i=0;i<8;i++)
	{
		for(int j=0;j<4;j++)
		{
			strcpy(bus[p].seat[i][j],"Empty");
		}
	}
}
void a::show()
{
	int n;
	char number[5];
	cout<<"Enter bus no: ";
	cin>>number;
	for(n=0;n<=p;n++)
	{
		if(strcmp(bus[n].busn,number)==0)
			break;
	}
	while (n<=p)
	{
		vline('*');
		cout<<" Bus no: \t"<<bus[n].busn
		<<"\n Driver: \t"<<bus[n].driver<<"\t\t Arrival time:\t"
		<<bus[n].arrival<<"\t Departure time:\t"<<bus[n].depart
		<<"\n From:\t\t"<<bus[n].from<<"\t\t To: \t\t\t"<<
		bus[n].to<<"\n";
		vline('*');
		bus[0].position(n);
		int a=1;
		for (int i=0;i<8;i++)
		{
			for(int j=0;j<4;j++)
			{
				a++;
				if(strcmp(bus[n].seat[i][j],"Empty")!=0)
					cout<<"\n The seat no "<<a-1<<" is reserved for "<<bus[n].seat[i][j]<<" .";
			}
		}break;
	}	if(n>p)
			cout<<"enter correct bus no.";
}
void a::position(int l)
{
	int s=0,p=0;
	for(int i=0;i<8;i++)
	{
		cout<<"\n";
		for(int j=0;j<4;j++)
		{
			s++;
			if(strcmp(bus[l].seat[i][j],"Empty")==0)
				{
					cout.width(5);
					cout.fill(' ');
					cout<<s<<".";
					cout.width(10);
					cout.fill(' ');
					cout<<bus[l].seat[i][j];
					p++;
				}
			else
				{
					cout.width(5);
					cout.fill(' ');
					cout<<s<<".";
					cout.width(10);
					cout.fill(' ');
					cout<<bus[l].seat[i][j];
				}
		}
	}
		cout<<"\n\n There are "<<p<<" seats empty in Bus No: "<<bus[l].busn;
}
void a::avail()
{
	for(int n=0;n<p;n++)
	{
		vline('*');
		cout<<"Bus no: \t"<<bus[n].busn<<"\nDriver: \t"<<bus[n].driver<<"\t\tArrival time:\t"<<bus[n].arrival<<"\tDeparture Time: \t"<<bus[n].depart<<"\n From: \t\t"<<bus[n].from<<"\t\t To: \t\t\t"<<bus[n].to<<"\n";
		vline('*');
		vline('_');
	}
}
int main()
{
	int w;

	while(1)
	{
		cout<<"\n\n\n\n";
		cout<<"\t\t\t 1.Install\n\t\t\t 2.Reservation\n\t\t\t 3.Show \n\t\t\t 4.Buses Available. \n\t\t\t 5.Exit";
		cout<<"\n\t\t\t Enter your choice:-> ";
		cin>>w;
		switch(w)
		{
			case 1:
			bus[p].install();
			break;
			case 2:
			bus[p].allotment();
			break;
			case 3:
			bus[0].show();
			break;
			case 4:
			bus[0].avail();
			break;
			case 5:
			exit(0);
		}
	}
}

A few comments about this code...
1) bad things happen when you use the dreaded word 'goto' . The block of code where you've used goto could be easily changed to use a do..while loop instead.

2) avoid using global variables - bus and p don't really need to be global

3) Use C++ strings instead of char[] - the C++ string header is <string>

4)

Code:

for (int i=80;i>0;i--)//Here i's value will depend on your computer.

i will be exactly the same regardless of your computer - what makes you think otherwise?

5)

Code:

int seat;

You already have a member variable of class 'a' called seat - reusing the name inside a member function is bad style.

6)Some of your class member functions don't actually do anything to the objects which they are called - instead they manipulate global variables - you really need to rethink the design of your code.



There could be other problems too, but that's what stuck out to me so far

ohh...thanks for ur comment....
i will alter to be better......