Программирование циклов while, for, do.while

#include <iostream>
 
using namespace std;
double factorial(int a)
{
    if (a == 0)
        return 1;
    else
        return a*factorial(a - 1);
}
int main()
{
    /*double a;
    cout << "Input a: ";
    cin >> a;
    double b;
    cout << "Input b: ";
    cin >> b;
    double n;
    cout << "Input n: ";
    cin >> n;
    double h;
    cout << "Input h: ";
    cin >> h;
    */
    double a = 0.1;
    double b = 1;
    double n = 100;
    double h = 0.1;
    double func;
    cout << "-------------------------------------------\n";
    cout << "|\tY(x)\t||\tS(x)\t||Y(x)-S(x)\t|\n";
    for (double x = a; x <= b; x += h)
    {
        double sum = 0;
        func = (exp(x) + exp(-x)) / 2;
        for (int i(0); i <= n; i++)
        {
            sum += pow(x, 2*i) / factorial(2 * i);
        }
        double f = func - sum;
        cout << "|  " << func << "\t||  " << sum << "\t|"
            << "| " << f << "\t|\n";
    }
    cout << "-------------------------------------------\n";
    system("pause");
    return 0;
}

#include <iomanip>

cout<<fixed<<setprecision(7) << "|  " << func << "\t||  " << sum << "\t|"
            << "| " << f << "\t|\n";

#include <iostream>
 
using namespace std;
 
int main() {
    double i = 1.4;
    double j = 1.4;
    double k = 1.4;
    double w = 4.2;
    cout << w - i - j - k << endl;
    system( "pause" );
    return 0;
}