Solution of Heat Equation C++

#include<iostream>
#include<iomanip>
#include<cmath>
using namespace std;
#define XEND 8
#define TEND 5

float f(int x)
{
return 4*x-(x*x)/2.0;
}

int main()
{
float u[XEND+1][TEND+1],h=1.0,k=0.125;
float csqr,alpha,ust,uet;
int i,j;

cout<<"Enter the square of 'c'"<<endl;
cin>>csqr;

alpha=(csqr*k)/(h*h);

cout<<"Enter the value of u[0,t]"<<endl;
cin>>ust;

cout<<"Enter the value of u["<<XEND;
cout<<",t]"<<endl;
cin>>uet;

cout<<fixed;

for(j=0;j<=TEND;j++)
u[0][j]=u[XEND][j]=ust;

for(i=1;i<=XEND-1;i++)
u[i][0]=f(i);

for(j=0;j<=TEND-1;j++)
for(i=1;i<=XEND-1;i++)
u[i][j+1]=alpha*u[i-1][j]+(1-2*alpha)*u[i][j]+alpha*u[i+1][j];

cout<<"The value of alpha is ";
cout<<setw(4)<<setprecision(2)<<alpha<<endl;

cout<<"The value of u[i,j] are :-"<<endl;
for(j=0;j<=TEND;j++)
{
for(i=0;i<=XEND;i++)
cout<<setw(7)<<setprecision(4)<<u[i][j];
cout<<endl;
}
return 0;
}