problema joi inserare coloane

// Se da o matrice patratica de ordinul n. Sa se insereze dupa coloana k o coloana noua formata doar din 0.

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    int a[100][100],n,i,j,k;
    cout<<"n= ";cin>>n;
    cout<<"k= ";cin>>k;
    for (i=1;i<=n;i++)
    for (j=1;j<=n;j++)
    {
        cout<<"a["<<i<<"]["<<j<<"]= ";
        cin>>a[i][j];
    }
    for(j=n+1;j>=k+1;j--)
    for (i=1;i<=n;i++)
    a[i][j]=a[i][j-1];
    for (i=1;i<=n;i++)
    a[i][k]=0;

    for (i=1;i<=n;i++)
    {
        for(j=1;j<=n+1;j++)
        cout<<a[i][j];
        cout<<'\n';
    }
}