C++ wala SQL (Project)(currently not complete)

//now posting as TECHY 3 ;-)

//New- Database Capability (groundwork ready for that)

// Further idea- Have an option to save the tables/databases in a database, or different databases
//               Declare more classes to get 1 column, 2 column.. tables also, probably maximum 5 columns
//               Have option to give/change Row names
// Create unlimited number of tables in a database using Linked List
// Maintain both, database with maximum 5 tables and database with more capabilities

//Features to be depricated
// Database with limitation of upto 5 tables

//Programmer - Aditya Gupta

#include<iostream>
#include<stdlib.h>
#include<string.h>
//#include<fstream> // will be required when save in database supported
using namespace std;

void inline title(void){
system("cls");
cout<<"\tNAMASTE!...\n\nProgram-C++ wala SQL\nPrograammer - MR. ADITYA GUPTA (Techy15)\n\n";
}
struct Node{
int dat1,dat2,dat3;
Node *next;
};

class Table{  //NOTE: I HAVE REMOVED ALL COMMENTS, REFER TO THE LINKED LIST TEMPLATE FOR DETAILED COMMENTS
Node *top,*rear;
char name[], A[], B[], C[]; //table name and column names
int asize, bsize, csize;
int state; //state has values 0 and 1, ie 0 if the table has never been used (being empty but even used once will get state=1)
char type; //type has values 's' or 'n' (currently)
   //s-special, n-normal
   //special table is the table i wanted (ie. havihng row names also)
public: int nrow;
void Push(int a1,int a2,int a3);
void Push(int a1,int a2, int a3, int loc); //THIS IS NOT IN SQL! :p
void tPush(int a1, int a2, int a3); //Places a new entry at top (THIS IS NOT IN SQL!)
void RWHERE(int a1, int a2=-1, int a3=-1); //random where (NOT IN SQL!)
   //IN CASE USER DOESNT REMEMBER WHICH COLUMN THE ELEMENT HE REMEMBERS BELONGS TO
void WHERE(int a1, int a2, int a3); //where() is an updated & advanced form of search()
void WHERE(int a1, int a2); //SUGGESTION- WHERE() KE ANDAR HI TABLE DISPLAY KARWALO AND CHOICE TO EDIT/DELETE PUCHH LO
void WHERE(int a1);
void WHERE(); //asks which WHERE function will the user want to use
int noofrow();
void Pop(); //SUGGESTED IMPROVEMENTS- 1. write pop(int,int,int) [for that user will have to remember all three of these]
//                        2. (i) get a function like WHERE a1=2, a2=3, a3=4 (same as suggestion 1)
//                           (AVAILABLE NOW!)(ii) get a function like Where a1=3, a2=3; or any other combination, TO REDUCE NUMBER OF COLUMNS DISPLAYED
void Pop(int loc);
void disp();
Table(){ top=rear=NULL; nrow=0;
state=0; //table name not to be initialised, since if unused state=0, and if used then it will have a name!
}
void ALTER(); //to ask for columnn names and table name
~Table(){   //Q. WILL DESTRUCTOR REQUIRE DELETE STATEMENTS? (LIKE DELETE TOP; ETC. ?)
}
void help(); //shows 'demo' of the table types available
};

/*   //A TRIAL DEFINITION OF A CLASS 'DATABASE HAVING UNLIMITED NUMBER OF TABLES'
struct TabNode{
Table Tab;
TabNode *nexttab;
};

class LDatabase{  //for managing databses with more than 5 tables
TabNode *top, *rear;
Database(){
top=rear=NULL;
}
char filename[32];
public: void Save();  //FUNCTIONS SAME AS GIVEN IN COMMENTS OF OTHER DEFINITION OF CLASS
void del();
};

*/

class Database{  //for managing databases with at max 5 tables
char filename[30]; //filename to which database to be saved
int stat; //stat has two values -1, 1 and 2
  //stat has 0 when database OK, ie less than 4 tables used (4 tables with state=1)
  //stat has 1 when database about to fill, ie 4 tables used; when stat=1 shows warning that whether the user will require more than 5 tables in the particular database
  //stat has 2 when database filled, ie all 5 tables used
Table Tab1, Tab2, Tab3, Tab4, Tab5; //maximum 5 tables
public: void Save(); //saves to binary file; name of file as given by user
void del(); //deletes the data of this databse to a file
//Q. CAN IT REALLY BE DONE ACCURATELY? (I MEAN DOESNT FOUT.READ(...) REQUIRES DATA IN DEFINED FORM, AND NOT IRREGULAR)
void print(); //prints database to a text file, ie. a printable format


void transfer(TDatabase TDat); //Q. CAN IT REALLY BE DONE!???
   //To transfer the 5 tables to the new linked list database


Database(){
filename={'D','a','t','a','b','a','s','e',' ','u','n','u','s','e','d'};
//Table constructors will automatically be called
}
~Database(){
//Destructors of tables automatically called
}
}
};

void Table::Push(int a1, int a2, int a3){ //adds row at end
Node *ptr=new Node;
ptr->dat1=a1; ptr->dat2=a2; ptr->dat3=a3;
rear->next=ptr;
ptr->next=rear;
rear=ptr; nrow=noofrow();
}
void Table::Push(int a1, int a2, int a3, int loc){
Node *temp=new Node,*ptr=new Node; temp->next=top; ptr->dat1=a1; ptr->dat2=a2; ptr->dat3=a3;
if(loc>(nrow+1)) cout<<endl<<loc<<" rows are not present in the table. So unable to add row to that location";
//added +1 since if there are n rows already, n+1 location will be a valid location to push row
else if(loc==nrow+1) Push(a1,a2,a3); //if push location provided is at end
else if(loc==1) tPush(a1,a2,a3);
else { for(int i=1;i<loc;i++) temp=temp->next; ptr->next=temp->next; temp->next=ptr; nrow=noofrow();  }
}
void Table::tPush(int a1, int a2, int a3){
Node *ptr=new Node, *temp; //Q. IS IT NECESSARY TO WRITE "NODE *PTR=NEW NODE"??
ptr->dat1=a1; ptr->dat2=a2; ptr->dat3=a3;
temp=top; top=ptr; ptr->next=temp; nrow=noofrow();
//Q. SHOULD/CAN I DELETE *TEMP WITHOUT AFFECTING ANY NODE??
}
void Table::Pop(){ Node *temp;
if(nrow==1) {
rear=top;
top=top;
delete temp;
}
else { Node *temp=new Node,*temp2=new Node; temp->next=top;
for(int i=1; i<nrow; i++) temp=temp->next; temp2=temp->next; //temp2 is the node to be deleted
temp->next=temp2->next; temp2->next=NULL; delete temp2;
} nrow=noofrow();
}
void Table::Pop(int loc){
Node *temp=new Node,*temp2=new Node; temp->next=top;
for(int i=1; i<loc; i++) temp=temp->next; temp2=temp->next; //temp2 is the node to be deleted
temp->next=temp2->next; temp2->next=NULL; delete temp2;  nrow=noofrow();
}
void Table::WHERE(int a1){
cout<<"   "; puts(A); cout<<"   |   "; puts(B); cout<<"   |   "; puts(C); cout<<endl;
Node*temp=top;
for(int i=0;i<nrow;i++)
{
if(temp->dat1==a1) { cout<<"   ";
if(asize%2==0) for(int j=0;j<(asize/2)-1;j++) cout<<" ";
else for(int j=0;j<(asize/2)-2;j++) cout<<" ";
cout<<temp->dat1; cout<<"  |";
if(bsize%2==0) for(int j=0;j<(bsize/2)-1;j++) cout<<" ";
else for(int j=0;j<(bsize/2)-2;j++) cout<<" "; cout<<temp->dat2; cout<<"  |";
if(csize%2==0) for(int j=0;j<(csize/2)-1;j++) cout<<" ";
else for(int j=0;j<(csize/2)-2;j++) cout<<" ";
cout<<temp->dat3; temp=temp->next; }
}
}
void Table::WHERE(){
int chc,a,b,c;
if(top==rear) { cout<<"Table is empty";
}
else {
rechc:
cout<<"\nHow many elements do you remember in columnwise order ? "
<<"\n1. All three\n2. First two\n3. Only first\n4. I remember one number but dont remember the coulumn\n";
switch(chc){
case 1: cout<<"Enter the numbers in order: "; cin>>a>>b>>c; WHERE(a,b,c); break;
case 2: cout<<"Enter the numbers in order: "; cin>>a>>b; WHERE(a,b); break;
case 3: cout<<"Enter the number: "; cin>>a; WHERE(a); break;
case 4: cout<<"Enter the number: "; cin>>a; RWHERE(a); break;
default: cout<<"Invalid Choice. Enter again..."; goto rechc; break;
} }
}
void Table::ALTER(){
cout<<"\nWhat name would you like to give this table? "; gets(name);
cout<<"\nEnter the names of column : \nColumn 1 -> "; gets(A);
cout<<"\nColumnn 2 -> "; gets(B);
cout<<"\nColumn 3 -> "; gets(C); cout<<endl;  asize=strlen(A); bsize=strlen(B); csize=strlen(C); //in case user changes name of columns, so will the lengths change
}
int Table::noofrow(){
Node *temp; int count=0;
temp=top; while(temp!=rear) { count++; temp=temp->next;
}
delete temp;  //Har jagah temp ko delete mat kar dena nahi to kabhi uski location wala node hi delete ho jayega, here we didnt need it to point to a data, so i deleted it
return count+1;  //adding 1 to compensate for last element since loop couldnt count the last element
}
void Table::disp(){
Node *temp=top;
if(top==rear) cout<<"Table is empty";
else{ cout<<"   "; puts(A); cout<<"   |   "; puts(B); cout<<"   |   "; puts(C); cout<<endl; }
for(int i=0;i<nrow;i++) //now printing table... (no need to write as SQL.noofrow, since we are inside the class for now)
{
cout<<"   ";
if(asize%2==0) for(int j=0;j<(asize/2)-1;j++) cout<<" "; //for printing sufficient number of spaces to look neat
else for(int j=0;j<(asize/2)-2;j++) cout<<" ";
cout<<temp->dat1; cout<<"  |"; // *THIS IS THE PLACE WHERE KNOWLEGDE OF GRAPHICS.H CAN REALLY HELP
if(bsize%2==0) for(int j=0;j<(bsize/2)-1;j++) cout<<" ";
else for(int j=0;j<(bsize/2)-2;j++) cout<<" ";
cout<<temp->dat2; cout<<"  |";
if(csize%2==0) for(int j=0;j<(csize/2)-1;j++) cout<<" ";
else for(int j=0;j<(csize/2)-2;j++) cout<<" ";
cout<<temp->dat3<<endl;
temp=temp->next;
}
}

int main()
{
title();
cout<<"This will create a table with three columns";
Table Tab1; char ch='Y'; int choice,a,b,c,l; //l is location
Tab1.ALTER();
cout<<"\nYou can change the column names whenever you want (ALTER)";
rechose:
do{
cout<<"\nChoose any one of the options : "
<<"1. ALTER\n2. INSERT\n3. SELECT * FROM TABLE\n4. WHERE\n5. DELETE\n";
cin>>choice;
switch(choice){
case 1: Tab1.ALTER(); break;
case 2: cout<<"Enter the values to insert (in respective order) :\n"; cin>>a; cout<<'\t'; cin>>b; cout<<"\t\t"; cin>>c; //intentional combination of \t
        Tab1.Push(a,b,c); break;
case 3: Tab1.disp(); break;
case 4: Tab1.WHERE(); break;
case 5: if(Tab1.nrow==0) cout<<"Table is already empty...";
else {
cout<<"If you want to delete the last element, enter 0\nElse you will be shown the table, then enter the row number to be deleted : "; cin>>l;
if(l==0) Tab1.Pop();
else { Tab1.disp(); cout<<"\nNow enter the row number to be deleted : "; cin>>l;
Tab1.Pop(l);
} break;
default: cout<<"\n\n"<<choice<<" is an invalid choice. Try again..."; goto rechose; break;
}
cout<<"\nDo you want to get to the menu again ? (y/n)"; cin>>ch; }
}while(ch=='Y'||ch=='y');


//cout<<"Do you want another table?" //This will be added when it supports saving to database, in case it is not being saved
                                    //then in that case the so called feature of multiple tables will just be worthless
return 0;
}

/* THINGS READY TO WORK->
. Display (ie. disp())
. ALTER
. INSERT
. DELETE
.
*/
/*
FEATURES AVAILABLE HERE BUT NOT IN SQL->
    . RANDOM WHERE ie. doesnt want you to remember which column the element entered by you is in, it will print all rows , in which at least one column contains that number
. INSERT AT TOP ie. inserting just entered row at top instead of bottom
. INTENTIONAL INSERT ie. inserting row whereever you want it to be
. ALTER TABLE NAMES ie. change the name of table
.
. MORE FEATURES WILL BE ADDED IN COURSE OF TIME(AND ON BASIS OF 'YOUR' SUGGESTIONS)
*/