Ad:

C++ Discussion Thread
Unsolved
Views: 11721

Aug 26th, 2004

pascals triangle

Expand Post »

hi
i want to display pascals triangle on computer screen.the pascals triangle
goes like this. and what is logic.
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1
1 5 10 10 5 1 and so on.

Similar Threads

Custom pascal triangle ? in C
Pascal Triangle program that needs to convert from C to C# in C
HELP!!! - Wanted : Pascal's Triangle with loops ? in C#
pascals triangle in C++
Pascals triangle (Functions) in C++

let us c

Reputation Points: 10

Solved Threads: 1

Newbie Poster

Offline

17 posts
since Aug 2004

Permalink

Aug 28th, 2004

Re: pascals triangle

Hi there are many logics behind this problem. This is the simple logic. Though it is inefficient, this will give you a better approach to this program

a[0] = 1
for(i=0;i<n;i++){
for(j=0;j<=i;j++){
Value_to_print = a[j-1]+a[j];
/* Print the values in the order you want */
}
a[j] = 0
a[j-1] = Value_to_print
}

ganesh

Reputation Points: 12

Solved Threads: 0

Newbie Poster

Offline

2 posts
since Aug 2004

Permalink

Sep 2nd, 2004

Re: pascals triangle

Well, you can try this code, but I don't know if it will work beyond n=9.

C++ Syntax (Toggle Plain Text)
#include <iostream.h>
#include <conio.h>
 
/* This program creates a half pyramid of nos. Created on 12.6.2k3. */
 
void main()
 
{
 int n, i, r;
 cout<<"Enter the number of numbers: ";
 cin>>n;
 if (n>9)
 cout<<"\n This won't work out. ";
 else
 {
  for (i=1; i<=n; i++)
  {
   for (r=1; r<=i; r++)
   {
    cout<<r;
   }
   cout<<endl;
  }
 }
 getch();
}
 
/* Output:
Enter the number of numbers: 7
1
12
123
1234
12345
123456
1234567
 
*/
#include <iostream.h>
#include <conio.h>

/* This program creates a half pyramid of nos. Created on 12.6.2k3. */

void main()

{
 int n, i, r;
 cout<<"Enter the number of numbers: ";
 cin>>n;
 if (n>9)
 cout<<"\n This won't work out. ";
 else
 {
  for (i=1; i<=n; i++)
  {
   for (r=1; r<=i; r++)
   {
    cout<<r;
   }
   cout<<endl;
  }
 }
 getch();
}

/* Output:
Enter the number of numbers: 7
1
12
123
1234
12345
123456
1234567

*/

btw, I didn't know it was called a pascal's triangle. I used to refer to it just as a no. pyramid or whatever.

iamboredguy

Reputation Points: 12

Solved Threads: 0

Newbie Poster

Offline

23 posts
since Aug 2004

Permalink

Aug 6th, 2010

Re: pascals triangle

program by iamboredguy is not a Pascal Triangle !!
Pascal Traingle is expected to give following sequence.
1
1 1
1 2 1
1 3 3 1
1 4 6 4 1

Last edited by manali04; Aug 6th, 2010 at 4:15 am. Reason: NA

manali04

Reputation Points: 10

Solved Threads: 0

Newbie Poster

Offline

3 posts
since Jul 2010

Permalink

Aug 6th, 2010

Re: pascals triangle

First logic feature to see is that it is always symmetric about the central value in one sequence, so you will probably just need to store or compute one half of each row (from start to middle) and repeat in reverse for the remainder of the row (taking into account even and odd number of elements).

The second logic feature to see is more evident in the normal display of the pascal triangle (forgive the ASCII art):

C++ Syntax (Toggle Plain Text)
            1
           / \
           1  1
          / \/ \
          1  2  1
         / \/ \/ \
         1  3  3  1
        / \/ \/ \/ \
        1  4  6  4  1
            ....
            1
           / \
           1  1
          / \/ \
          1  2  1
         / \/ \/ \
         1  3  3  1
        / \/ \/ \/ \
        1  4  6  4  1
            ....

From this it's clear that the operation that joins a \/ segment is the addition. So like in ganesh's pseudo-code, the basic idea is to add two adjacent elements of the previous row to get the corresponding element of the next row (except for the first element which is always 1 and the centre element of an odd-row which might be twice the element closest to centre of the even-row above it).

Show us some code of your own, and we can help you further.

mike_2000_17

Featured Poster

Reputation Points: 1437

Solved Threads: 398

Posting Virtuoso

Online

1,839 posts
since Jul 2010

Permalink

Aug 6th, 2010

Re: pascals triangle

I believe you can use the coefficient formula.

sunyifei23

Reputation Points: 10

Solved Threads: 3

Newbie Poster

Offline

11 posts
since Jul 2010

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

Previous Thread in C++ Forum Timeline: how to remove a particular pattern and retain other patterns in a string

Next Thread in C++ Forum Timeline: How do i work on a 12 digit integer in c++

DaniWeb Message

Cancel Changes

User Name
Password