mw lab 3

#include <iostream>
#include <cmath>
#include <string>
#include <iomanip>

using namespace std;

void display_header(void);
void display_result(double atime, double ampere, double voltage);
void display_max_result(double m_vol, double m_cur, double m_time);
bool check_number(string str)
{
    for (int i = 0; i < str.length(); i++)
    {
        if (isdigit(str[i]) == false)
        {
            return false;
        }
        else
            return true;
    }
}

int main()
{
    int j, counter;
    string resistance, imax, frequency;
    double r, v, i_max, f, t, max_current, max_time, max_voltage = 0, i, time, trig, deg, atime;
    const double pi = 3.14159265359;
    char again;
    do
    {
        cout << "Please ONLY enter Number"<<endl;
        do
        {
            cout << "Enter your resistance value,R: ";
            cin >> resistance;
        } while (check_number(resistance)!=1);
        r = stod(resistance);
        do
        {
            cout << "Enter your Imax value,Im  (in Ampere): ";
            cin >> imax;
        } while (check_number(imax) != 1);
        i_max = stod(imax);

        do
        {
            cout << "Enter your frequency,f (in frequency): ";
            cin >> frequency;
        } while (check_number(imax) != 1);
        f = stod(frequency);


        display_header();


        for (t = 0; t <= 10; t++)
        {
            time = 100 * (t / f);
            atime = time * 0.001;
            trig = 2 * pi * f * (atime);
            i = i_max * sin(trig);
            v = i * r;

            display_result(time, i, v);

            if (v > max_voltage)
            {
                max_voltage = v;
                max_time = time;
                max_current = i;
            }
        }

        display_max_result(max_voltage, max_voltage, max_time);
        cout.flush();
        cin.ignore();
        cout << endl << "Do you wish to continue ? (Y/N)";
        cin >> again;
    } while (again == 'Y' || again == 'y');

    return 0;

}
void display_header(void)
{
    cout << showpoint << right;
    cout << endl << setw(12) << "Time(ms)" << setw(15) << "Current(A)" << setw(15) << "Voltage(V)" << endl;
}
void display_result(double atime, double ampere, double voltage)
{
    cout << fixed;
    cout << setw(12) << setprecision(2) << atime << setw(15) << setprecision(4) << ampere << setw(15) << setprecision(4) << voltage << endl;
}
void display_max_result(double m_vol, double m_cur, double m_time)
{
    cout << endl << "Vmax is: " << m_vol << "V occurs with current " << m_cur << " at time " << m_time;
}