permutaion function C++

[drummer0702]

Ok I just joined this board in hope I can ask this question and that I'm in the right place...

So I have to write a complete program that inputs n and k and prints out the p(n,k).

This is what I have so far and I'm pretty sure something is incorrect

#include <iostream>
using namespace std;
int main(){
int p,n,k;



cin>>n>>k;

for(P(n,k) = n! / (n - k)!);
{
double factorial(unsigned n) {
if (n == 1) return n;
return n * factorial(n-1);
}
cout<<"p("<<n<<','<<k<<")"<<p<<endl;
}




return 0;
}

Thanks in advance

[gerard4143]

Is p(n, k) a function?

do you mean your trying to calculate P(n, r) = n!/(n - r)!

[drummer0702]

yes thats what i mean

[gerard4143]

Well you should define your function outside of the main function like:

#include <iostream>
using namespace std;

double mypermutation(int x, int y);

int main()
{
     int p,n,k;
     cin>>n>>k;

     mypermutation(n, k);

     cout<<"p("<<n<<','<<k<<")"<<p<<endl;
     return 0;
}

double mypermutation(int x, int y)
{
    //does whatever it takes to calculate the permutation
    //return the answer as a double
}

[drummer0702]

Sry I'm quite the novice at this but where would that go again?

[smolloy]

With respect drummer0702, but gerard4143 pretty much gave you the answer!

If you check out the forum rules you'll see that homework questions aren't allowed. We all had to figure it out in our day -- so do you

Do your best to figure out what gerard4143 meant, and we can try to answer any specific questions you have.

Welcome to the forums

[drummer0702]

Sorry about that. Yah thanks for what help you gave me I'll try and figure it out..Sorry again

[drummer0702]

Okay I figured out what you meant thank you...Now my only problem is that it saying there is a syntax error for 'for' and that something about old style formatting...Idk what the latter is

[wje_lf]

If you post the program which compiles with the syntax error, we will be better able to help you.