kwadrat z przekątną

#include <iostream>

/* run this program using the console pauser or add your own getch, system("pause") or input loop */
 using namespace std;
int main(int argc, char** argv) {
    int a,x,k;
    cin>>a;
    for (int i =1 ; i<=a;i++)
    cout<<"#";
    cout<<endl;
    k=-1;
    for (int i=1;i<=a-2;i++){

        k++;
            cout<<"#";
        for (int j=0 ;(j<k);j++)

        cout<<" ";
        cout<<"#";

        for (x=1;x<=a-k-3;x++)
        cout<<" ";
        cout<<"#"<<endl;}
        for (int j=0;j<a;j++)
        cout<<"#";




    return 0;
}