#include <iostream>
#include <fstream>
using namespace std;
int main() {
    ofstream file;
    file.open("input.txt");
    double dt = 0.1;
    double T0 = 100.0;
    double Tl = 50.0;
    double dx = 2.0;
    double l = 10.0;
    double T_init[6] = { T0,0,0,0,0,Tl };
    double T[6] = { T0,0,0,0,0,Tl };
    double lambda = 0.835*(dt / (dx*dx)); //0.835 => heat exchange factor
    for (int j = 0; j<1 / dt; j++) {
        for (int i = 1; i<l / dx; i++){
            T[i] = T_init[i] + lambda*(T_init[i + 1] - 2 * T_init[i] +
                                       T_init[i - 1]);
            cout << endl << T[i];
        }
        cout << endl << "///////////////////////" << endl;
        for (int i = 0; i<6; i++)
            file << T_init[i] << " ";
        file << endl;
        for (int i = 0; i<6; i++)
            file << T[i] << " ";
        file << endl;
        for (int i = 1; i<5; i++)
            T_init[i] = T[i];
    }
    return 0;
}