Gaussian Jordan Program C++ - Program Gaus Jordan C++

#include <iostream>
#include<cstdlib>
#include<cmath>
#include<conio.h>
using namespace std;



int main()
{
    int i,j,k,n;
    double tmp, x, a[20][20],z,y[10];
    cout<<"\nInsert size of matrix : ";
    cin>>n;
    cout<<("\nInsert Matrix x : \n");
    for(i=1; i<=n; i++)
    {
        for(j=1; j<=(n); j++)
        {
            cout<<" X["<<i<<"]["<<j<<"] :";
            cin>>a[i][j];
        }
    }
cout<<"\nInsert Matrix Y : ";
  for(int i=1;i<=n;i++){
    cout<<" Y["<<i<<"]["<<j<<"] :";
   cin>>y[i];
   }
cout<<"\n";
cout<<"\nThe Matrix : "<<endl;
    for (int i=1;i<=n;i++){
     for(int j=1;j<=n;j++){
      cout<<a[i][j]<<"\t";
     }
      cout<<"|b"<<i<<"|";

       cout<<"\t"<<y[i]<<endl;
      }
      cout<<endl;
      for(int i=1;i<=n;i++){
       cout<<"\nStep "<<i<<endl;
       tmp=a[i][i];
       for(int j=1;j<=n;j++){
        a[i][j]=a[i][j]/tmp;
       }
       y[i]=y[i]/tmp;
       for (int z=0;z<=n;z++){
        if(z!=i){
         tmp=a[z][i];
         for(int j=i;j<=n;j++){
          a[z][j]=a[z][j]-(tmp*a[i][j]);}
         y[z]=y[z]-(tmp*(y[i]));
        }
       }
    for (int i=1;i<=n;i++){
     for(int j=1;j<=n;j++){
      cout<<a[i][j]<<"\t";
     }
      cout<<"|b"<<i<<"|";

       cout<<"\t"<<y[i]<<endl;
      }
      cout<<endl;
     }
     cout<<"\nThe results :"<<endl;
     for(int i=1;i<=n;i++){
      cout<<"X"<<i<<" = "<<y[i]<<endl;
     }
getch();
}