n!/k!(n-k)!

[smemamian]

hi

i get this message in .net :

Error 1 error C2540: non-constant expression as array bound \documents\visual studio 2010\projects\test3\test3\test3.cpp 18 1 Test3

Error 2 error C2440: 'initializing' : cannot convert from 'long (*)[1]' to 'long *' \documents\visual studio 2010\projects\test3\test3\test3.cpp 18 1 Test3
Error 3 error C2109: subscript requires array or pointer type \documents\visual studio 2010\projects\test3\test3\test3.cpp 24 1 Test3

http://up.clip2ni.com/i/images/gw01igmnagww1ojhmfl8.jpg

// Test3.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include <iostream>

long int bin(int n,int k);
int _tmain(int argc, _TCHAR* argv[])
{
	std::cout << " example : \n" << bin(10,5) << "\n" ;

	return 0;
}

long int bin(int n , int k)
{
 // long  int b[n][k];
	long int *b = new long int[n][k];
 int i,j;
for (i=0;i<n;i++)
   for (j=0;j<i;j++)   //   For (j=0;j< min(I,k);j++)
   {
    if(j==0 || j==i)
       b[i][j]=1;
else
        b[i][j]=  b[i-1][j]+b[i-1][j-1];
}
return b[n][k];
}

why ?!
tnx

[cire]

Your code appears to have nothing to do with the subject of the thread or the image you linked, other than having variables named n and k.

You don't want a two dimensional array here if the subject is accurate. What are you trying to do exactly? Describe the algorithm you're attempting to implement in bin.

[MikeyBoy]

That's not how you dynamically allocate 2-dimensional arrays.

I'm sure a suitable Google search will find you some examples of how to do it. My advice would be to stop using C-style arrays, and start using STL vectors instead.

[smemamian]

ok

please look this picture :


http://up.clip2ni.com/i/images/xp3hvwxjuy205uyob2le.jpg

[LaboPie]

it's generally a bad code habit for a c++ beginner declare a 2 dimensional array with pointer. It's so much old style :)

However if you want to do it no matter what, you should declare a long int double pointer

long int **b

otherwise you are declaring a one dimensional array.