с массивом

#include <iostream>
using namespace std;
int **creat(int &n, int &m)
{
        cout << "n="; cin >> n; cout << "m="; cin >> m;
        int **mas = new int*[n];
        for (int i = 0; i < n; ++i)
                mas[i] = new int[m];
        for (int i = 0; i < n; ++i)
                for (int j = 0; j < m; ++j)
                {
                        cout << "mas[" << i << "][" << j << "]="; cin >> mas[i][j];
                }
        return mas;
}
int main()
{
        int n, m,maxj;
        cout << "n="; cin >> n; cout << "m="; cin >> m;
        int **a = creat(n, m);int max;
        for (int i = 0; i < n; ++i)
             {max=a[i][0];
               maxj =0;
                for (int j = 0; j < m; ++j)
                        if (a[i][j]>max)
       {
                            max = a[i][j];
                            maxj=j;
       }
                    a[i][maxj]*=-1;
        }
cout<<"Полученная матрица:";
       for(int i=0;i<n;i++)
{
          for(int j=0;j<n;j++)
               cout<<a[i][j]<<" ";
cout<<endl;
}
        for (int i = 0; i < n; ++i)
                delete[]a[i];
        delete[]a;
        system("pause");
        return 0;
}