public:static double fn(int T,double x)
                   {
                       if (x>=0)
                           return T;
                       else if(x<0)
                           return 0;
                   }

public:static double qt0(double t)//Finite condition
           {
               if (t<=0)
                   return 0;
               else
                   return t;
           }

My parameters is:

hx (step on space)= 0.1

ht (step on time) = 0.5

Nx (quantity of steps on x axis) = 10;

Nt (quantity of steps on t axis) = 12;

wx[] - this is array of all steps on space;

wt[] - this is array of all steps on time;

wht[][]-final array when will be results;

for(int i = 0;i<Nx;i++)
                     {
                         wx[i+1]=wx[i]+hx;
                         wht[0][i]=fn(T,wx[i]);//funtion.
                     }

                     for(int j = 0;j<Nt;j++) //
                     {
                         wt[j+1]=wt[j]+ht;
                         wht[j+1][0] = qt0(wt[j+1]);
                     }

for(int j = 0;j<Nt;j++)
                         {
                              for(int i = 0;i<Nx;i++)
                             {
                    wht[j+1][i]=-a*(ht*(wht[j][i+1] + wht[j][i])/hx) + (wht[j][i]);
                             }
                         }