TDDE18CppCourse/lab1/select_and_rep.cc

/* 
Lab 1 - TDDE18 - Selection and repetition
Last modification : 2020-09-03
*/

#include <iostream>
#include <iomanip>

/*
1-1 --> done

Try to avoid comments on the same line as code
--> done

Statements should have it's own block declared underneath
it so its easier to read.
    Ex  if()
        {
--> done

use std:setw() and std::setfill(-) instead of a for loop to write
--> done

Use the give information to calculate the steps and then use a for loop
instead of while() and adding the stride.
Adding floats will eventually end up in errors because a float isn't precise
which you avoid by using doubles, but worth noting.
By calculating the amount of steps its guaranteed no errors will occur
--> done: change the final while loop to a for loop
*/

using namespace std;

int main() 
{
    double first_price{};
    double last_price{};
    double stride{};
    double tax{};
    bool is_ok{false};

    // I/O begin
    cout << "INPUT PART" << endl;
    cout << "==========" << endl;

    // For each value, we check the consistency of the given value
    while (!is_ok) 
    {
        cout << "Enter first price: ";
        cin >> first_price;

        if (first_price >= 0) 
        {
            is_ok = true;
        }
        else 
        {
            cout << "ERROR: First price must be at least 0 (zero) SEK" << endl;
        }
    }
    
    is_ok = false;
    while (!is_ok) {
        cout << "Enter last price: ";
        cin >> last_price;

        if (last_price >= first_price) 
        {
            is_ok = true;
        }
        else 
        {
            cout << "ERROR: The last price must be greater than or equal to the first price (" 
                << first_price << " SEK)" << endl;
        }
    }

    is_ok = false;
    while (!is_ok) {
        cout << "Enter stride     : ";
        cin >> stride;

        if (stride >= 0.01) 
        {
            is_ok = true;
        }
        else 
        {
            cout << "ERROR: Stride must be at least 0.01" << endl;
        }
    }
    
    is_ok = false;
    while (!is_ok) {
        cout << "Enter tax percent: ";
        cin >> tax;

        if (0 <= tax && tax <= 100) 
        {
            is_ok = true;
        }
        else 
        {
            cout << "ERROR: The tax value cannot be negative or greater than 100%" << endl;
        }
    }
    cout << endl;

    // Percent correction
    tax = tax * 0.01;

    cout << "TAX TABLE" << endl;
    cout << "=========" << endl;
    cout << setw(12) << "Price" << setw(12) << "Tax" << setw(20) << "Price with tax" << endl;
    cout << setfill('-') << setw(45) << " " << setfill(' ') << endl;

    // We calculate the necessary number of iteration 
    int number_of_interation = static_cast <int> (last_price - first_price)/stride;

    double price = first_price;
    for (int i = 0; i <= number_of_interation; i++)
    {
        cout << fixed << setprecision(2) << setw(12) 
            << price << setw(12) 
            << price*tax << setw(20) 
            << price + price*tax << endl;
        price += stride;
    }

    return 0;
}