#include <stdio.h>
int main(int argc, char *argv[]) {

  int j, jbar = 50;
  double dx=1.0, dt=0.1, sig=1.0, endtime=10.0, time=0.0, TL=400.0, TR=0.0;
  double T[jbar + 2], Tnew[jbar + 2];

  for (j = 0;  j <= jbar+1;  j++) { T[j] = 0.00; }

  while ( time <= endtime ) {

    T[0] = 2.0*TL - T[1];
    T[jbar+1] = 2.0*TR - T[jbar];

    for (j = 1;  j <= jbar;  j++) {
      Tnew[j] = T[j] + sig*dt*(T[j+1]+T[j-1]-2.0*T[j])/dx/dx;
    }

    for (j = 1;  j <= jbar;  j++) { T[j] = Tnew[j]; }
    time += dt;

  }

  for (j = 1;  j <= jbar;  j++) {
    printf("x %11.6lf T %11.6lf\n", ((double)(j-1)+0.5)*dx, T[j]);
  }

}