The MultiMatics - A C++ Project

/*This program is a very basic one, but still a quite long use, making it useful for learning*/
/* I HAVE WRITTEN THIS BY MYSELF, and I give FULL RIGHTS TO ANYONE willing to take this code for learning purpose, or for experimenting with this! And, 'please' don't use this for "copy&paste" purposes*/

#include<iostream>
#include<conio.h>
#include<math.h>
#include<stdlib.h>
#define 1/0 Not_Defined
using namespace std;
void delay(void)
{
    for(int i=0;i<3000;i++)
    for(int j=0;j<9090;j++) {}
}
void expan(void);
long double fact(long int a);
//long double pow(long int x,long int y) has been removed by me due to no need
void pac();
void trigo(void);
void genac();
int main()
{
    float a,b; long int x,n,p,choice;
    punarvichaar:
    clrscr();
    cout<<"Enter : "<<endl<<"@ 1 for expansion of (1+x)^n"<<endl
<<"\n@ 2 for factorial calculation"<<"@ 3 for power calculation"<<endl<<"@ 4 Permutations and Combinations"<<endl
    <<"@ 5 for Trigonometric calculations"<<"\n@ 6 for General Arithmetic Calculations and others"<<"\n@ 7 To exit"<<"\n\n";
    cin>>choice;
    switch(choice)
    {
        case 1:       clrscr(); expan();
                      break;
    case 2:     clrscr();
                    cout<<"\n\nEnter the number : "<<"\n";
                    cin>>a;
                    cout<<endl<<fact(a)<<endl;
                 break;
    case 3:     clrscr();
                cout<<"\n\nEnter number and power:";
                cout<<"\nNumber : ";     cin>>a;
                cout<<"\nPower : " ;     cin>>b;
                cout<<"\n\n"<<a<<" to the power "<<b<<" is "<<"\n"<<pow(a,b); break;
    case 4: clrscr();
            pac();
            break;
    case 5: clrscr();
            trigo();
            break;
    case 6: clrscr();
            genac();
            break;
    default:   cout<<endl<<"Kripya phir se prayas kare...@-@"<<endl;
                delay(); goto punarvichaar;
       break;    }
    getch();
}
void expan(void)
{
    int x,n;
    cout<<"\n\nEnter the values of x and n [in computation of (1+x)^n]";
    cout<<"\n\n x : ";    cin>>x;
    cout<<"\n\n n : ";    cin>>n;
    long double exp=0.0;
   for(long double i=0;i<=97675684;i++)
   {
   exp+=fact(n)*pow(x,i-1)/(fact(i)*fact(n-i));
   }
   cout<<"\n\n"<<exp;
}
long double fact(long int a)
{
long double factorial=1;
while(a!=0)
{   factorial*=a;
    a--;  }
return factorial;
}
//long double pow(long int x,long int y) has been removed by me due to no need
void pac(int n,int r)
{
    clrscr();
    cout<<"\n\nEnter the number of total objects(index), and the no. of places(r)";
    cout<<"\nIndex(n) : "; cin>>n;
    cout<<"\nNo. of Places(r) : "; cin>>r;
    cout<<"\n\nPermutations : "<<fact(n)/fact(n-r);
    cout<<"\n\nCombinations : "<<fact(n)/(fact(r)*fact(n-r));
    cout<<"\n\nCircular Permutations : "<<fact(n-1)/(fact(r-1)*fact(n-r));
}
void trigo(void)
{
  clrscr();
  int ch,x;
  cout<<"Enter what u need (Enter 1,2,3 or 4):"<<"\n\n1. Claculation of Trigonometric Functions"<<"\n\n2. Calculation of T-functions for Half Angles"
  <<"\n\n3. Lenght of sides of triangles if any two/one is given"<<"\n\n4. Back to main menu"<<"\n\n";
  switch(ch)
  {
    case 1: cout<<"Enter the value of x (in radians)";  cin>>x;
            cout<<"\n\nsinx = "<<sin(x);
            cout<<"\n\ncosx = "<<cos(x);
            cout<<"\n\ntanx = "<<tan(x);
            cout<<"\n\ncosecx = "<<1/sin(x);
            cout<<"\n\nsecx = "<<1/cos(x);
            cout<<"\n\ncotx = "<<1/tan(x);
            break;
    case 2: cout<<"Enter the value of x (in radians)"; cin>>x;
            cout<<"\n\nsin(x/2) = "<<sin(x/2);
            cout<<"\n\ncos(x/2) = "<<cos(x/2);
            cout<<"\n\ntan(x/2) = "<<tan(x/2);
            cout<<"\n\ncosec(x/2) = "<<1/sin(x/2);
            cout<<"\n\nsec(x/2) = "<<1/cos(x/2);
            cout<<"\n\ncot(x/2) = "<<1/tan(x/2);
            break;
    case 3: cout<<"Enter the lenght of two sides";
            break;
    case 4: break;
  }
}
void genac(void)
{
    clrscr();
    int a,b;
    cout<<"This section will help you in arithmetic calculations"
    <<"\n\nEnter two numbers one by one";
    cin>>a>>b;
    cout<<"\n\n"<<a<<" + "<<b<<" is : "<<a+b;
    cout<<"\n\n"<<a<<" - "<<b<<" is : "<<a-b;
    cout<<"\n\n"<<a<<" * "<<b<<" is : "<<a*b;
    cout<<"\n\n"<<a<<" / "<<b<<" is : "<<a/b;
}

/*ANY suggestions will be very helpful, and btw its me who will be more benefited, so THANX for that*/ /*I WILL NOT CLAIM IT MINE, any suggestions will be a great help*/