Combinations with factorial

Would somebody help me with this.

Let's take 4! (4 times 3 times 2 times 1 time = 24). This is easy to do but I want to have all 24 combinations on the screen.

Thanks

Code:

---


for (x=2; x>0; x--)
{ for (y=2; y>0; y--)
  { if(y==x) continue;
      cout<<x<<","<<y<<endl;
    }
}

---

There is a little code that will do it for 2!. You can expand on that for 4!.

You are creating *permutations*.
Here is a function for creating all permutations in order (there is one in STL too called next_permutation using templates):

Code:

---

#include <iostream>
void swap(int &n1,int &n2) {
    int temp=n1;
    n1=n2;
    n2=temp;
}
bool next_permutation(int *table, int length) {
    int key=length-1, i=length-1;
    while(key>0 && table[key]<=table[key-1])
        key--;
    if(key==0)return false;
    key--;
    while(table[key]>=table[i])
        i--;
    swap(table[key],table[i]);
    for(i=length-1,key++;key<i;key++,i--)
        swap(table[key],table[i]);
    return true;
}
int main () {
    int i, sequence[10]={1,2,3,4,5,6,7,8,9,10};
    do {
      for(i=0;i<10;i++)
        std::cout<<sequence[i]<<" ";
      std::cout<<std::endl;
    } while(next_permutation(sequence,10));
    return 0;
}

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Thanks for the solutions. Is it possible to get a solution so I don't have to specify in advance the number of elements in the array.
Fero

I''m just guessing 'cuz I didn't look carefully (I'm probably wrong, but whatever), but looking at golfinguy's post, try this:

Code:

---


void showStuff(int n)
{

for (x=n; x>0; x--)
{ for (y=n; y>0; y--)
  { if(y==x) continue;
      cout<<x<<","<<y<<endl;
    }
}

}

---

again, this is a wild guess based on a quick glance at golfinguy's post...