Gauss Elimination Method C++

#include<iostream>
#include<iomanip>
#include<cmath>

using namespace std;
#define N 4

int main()
{
float a[N][N+1],x[N],t,s;
int i,j,k;

cout<<"Enter the elements of the";
cout<<" augmented matrix rowwise"<<endl;
cout<<fixed;

for(i=0;i<N;i++)
for(j=0;j<N+1;j++)
cin>>a[i][j];
for(j=0;j<N-1;j++)
for(i=j+1;i<N;i++)
{
t=a[i][j]/a[j][j];
for(k=0;k<N+1;k++)
a[i][k] -= a[j][k]*t;
}

//Now printing the upper triangular matrix

cout<<"The upper triangular matrix is:-"<<endl;

for(i=0;i<N;i++)
{
for(j=0;j<N+1;j++)
cout<<setw(8)<<setprecision(4)<<a[i][j];
cout<<endl;
}

//Now performing back substitution

for(i=N-1;i>=0;i--)
{
s=0;
for(j=i+1;j<N;j++)
s += a[i][j]*x[j];
x[i]=(a[i][N]-s)/a[i][i];
}

//Now printing the results

cout<<"The solution is:-"<<endl;

for(i=0;i<N;i++)
{cout<<"x["<<setw(3)<<i+1<<"]=";
cout<<setw(7)<<setprecision(4)<<x[i]<<endl;}

return 0;
}