q199245791

#include <iostream>
#include <iomanip>
#include <stdlib.h>
#include <time.h>

using namespace std;

int main ()
{
    srand(time(NULL));
    int n;
    cin >> n;

    float **a = new float*[n];
    for (int i = 0; i < n; i++)
    {
        a[i] = new float[n];
        for (int j = 0; j < n; j++)
        {
            a[i][j] = rand() / (float)RAND_MAX * 2 - 1;
            cout << setw(7) << setprecision(3) << fixed << a[i][j];
        }
        cout << endl;
    }

    int r;
    cin >> r;
    for (int i = 0; i < n; i++)
        swap(a[r][i], a[i][i]);

    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < n; j++)
        {
            cout << setw(7) << setprecision(3) << fixed << a[i][j];
        }
        cout << endl;
        delete []a[i];
    }
    delete []a;
}