grapher.cpp

//Simple graphing calculator
#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <cmath>
using namespace std;

//constants are usually put in the global scope
const float size = 10;
string filename;

//void load();
char menu();
void linear(ofstream& output);
void quadratic(ofstream& output);
void cubic(ofstream& output);
void deleteData(ofstream& output);
//void exit();

//clrscr is a deprecated function used almost exclusively in Windows
//and a relic from Borland C++. This method only uses the standard library
void clrscr()
{
    for (int i = 0; i < 100; i++)
        cout << endl;
}

//Although void main() works on many systems, it is not and never has been
//standard. The system expects a return value of 0 when the program exits successfully.
//It is always expected to be int
int main()
{
    /*char bypass;
     //int o;data localization
     cout << "\n\n\t\t\t\tBYPASS CODE : ";  // BYPASS FOR LOADING
     bypass = cin.get();  //getch is not a standard function, cin.get() will get the
     //next char in the stream
     if (bypass == '+')
     {
     //goto main; NEVER ever ever ever ever ever ever use a goto. It makes the
     //the program all but impossible to debug
     }
     else
     load();
     //goto loading;*/

    cout << "Enter the location of the output file (default graph.txt): ";
    getline(cin, filename);
    if (filename == "")
        filename = "graph.txt";

    ofstream output;
    output.open(filename.c_str(), ios::app);

    char mode = menu();
    while (mode != 'x' && mode != 'X')
    {
        switch (mode)
        {
            case 'a':
            case 'A':
                linear(output);
                break;
            case 'b':
            case 'B':
                quadratic(output);
                break;
            case 'c':
            case 'C':
                cubic(output);
                break;
            case 'd':
            case 'D':
                deleteData(output);
                break;
            default:
                clrscr();
                cerr << "Invalid Choice" << endl;
                //goto main;
                break;
        }
        clrscr();
        mode = menu();
    }

    output.close();

    //The below statements are the same as the above,
    //but the switch is more convenient in this case.
    /*if (mode == 'a' || mode == 'A')
     linear(output);
     else if (mode == 'b' || mode == 'B')
     quadratic(output);
     else if (mode == 'c' || mode == 'C')
     cubic(output);
     else if (mode == 'd' || mode == 'D')
     deleteData(output);
     else if (mode == 'x' || mode == 'X')
     exit();
     // ROBUSTNESS
     else
     {
     cerr << "Invalid Choice" << endl;
     //goto main;
     menu();
     }*/
}

char menu()
{
    //main: NEVER EVER use GOTO

    //int loop; it is not a good idea to reuse a variable
    //in 2 loops, it can cause debugging issues is larger programs
    //any time penalty will be negligible

    /*for (int loop = 0; loop < 80; loop++)
     cout << "\f";*/
    cout << "\n\t----------------------------------------------------------------------\n"
         << "\t|                                                                    |\n"
         << "\t| «««««««««««««««««««««   GRAPHIC CALCULATOR   »»»»»»»»»»»»»»»»»»»»» |\n"
         << "\t|                                                                    |\n"
         << "\t----------------------------------------------------------------------\n"
         << "\n";
    /*for (int loop = 0; loop < 80; loop++)
     cout << "\f";*/
    cout << "\n\n"
         << " \n\n\t A--> LINEAR EQUATION \t\t D--> DELETE EXISTING DATA"
         << " \n\n\t B--> QUADRATIC EQUATION"  //\t\t R--> READ-ME"
         << " \n\n\t C--> CUBIC EQUATION \t\t X--> Exit"
         << "\n\n> ";

    return cin.get();
}

void linear(ofstream& output)
{
    clrscr();  // REFRESHING PAGE
    cout << "----- LINEAR EQUATION -----" << endl << "y = mx + b\n\n";

    float x, y, m, b;

    cout << "\nEnter coefficient of 'x': ";
    cin >> m;
    cout << "\nEnter Constant ('0' if None): ";
    cin >> b;

    cout << "Your Equation: y = " << m << "x + " << b << "\n\n\n";
    //there is no problem with the x coefficient, it just makes a horizontal line
    output << "Your Equation: y = " << m << "x + " << b << endl;

    //no reason to have an nsize variable, just use -size
    for (x = -size; x < size; x++)  // LOOP TO PRINT AT COORDINATES
    {
        y = (x * m) + b;
        output << " |" << setfill('-') << setw(y + 100)
               << "+\t" << "(" << x << ", " << y << ")"
               << endl;
    }

    clrscr();
    cout << "\n\nPlease check the output file.\n\n";
    cout << "PRESS ANY KEY TO RETURN TO THE MENU";
    cin.ignore();
    cin.get();

    cout << endl;
    //goto main;
}

void quadratic(ofstream& output)
{
    //quadratic:
    clrscr();  // REFRESHING PAGE
    cout << "----- QUADRATIC EQUATION -----" << endl
         << "x = m * y^2 + b\n\n";

    float x, y, a, b, c;

    cout << "Enter coefficient of x^2: ";
    cin >> a;
    cout << "Enter the coefficient of x: ";
    cin >> b;
    cout << "Enter Constant ('0' if None): ";
    cin >> c;

    cout << "Your Equation: y = " << a << " * x^2 + " << b << " * x + " << c << "\n\n\n";
    //there is no problem with the 0 as the coefficient,
    //it just makes a horizontal line
    output << "Your Equation: y = " << a << " * x^2 + " << b << " * x + " << c << "\n\n\n";

    //no reason to have an nsize variable, just use -size
    for (x = -size; x < size; x++)  // LOOP TO PRINT AT COORDINATES
    {
        y = (pow(x, 2) * a) + b * x + c;
        output << " |" << setfill('-') << setw(y + 100)
                       << "+\t" << "(" << x << ", " << y << ")"
                       << endl;
    }

    clrscr();
    cout << "\n\nPlease check the output file.\n\n";
    cout << "PRESS ANY KEY TO RETURN TO THE MENU";
    cin.ignore();
    cin.get();
    cout << endl;
    //goto main;
}

void cubic(ofstream& output)
{
    //quadratic:
    clrscr();  // REFRESHING PAGE
    cout << "----- QUADRATIC EQUATION -----" << endl
         << "x = m * y^2 + b\n\n";

    float x, y, a, b, c, d;

    cout << "Enter coefficient of x^3: ";
    cin >> a;
    cout << "Enter coefficient of x^2: ";
    cin >> b;
    cout << "Enter the coefficient of x: ";
    cin >> c;
    cout << "Enter Constant ('0' if None): ";
    cin >> d;

    cout << "Your Equation: y = " << a << " * x^2 + " << b << " * x + " << c << "\n\n\n";
    //there is no problem with the 0 as the coefficient,
    //it just makes a horizontal line
    output << "Your Equation: y = " << a << " * x^2 + " << b << " * x + " << c << "\n\n\n";

    //no reason to have an nsize variable, just use -size
    for (x = -size; x < size; x++)  // LOOP TO PRINT AT COORDINATES
    {
        y = (pow(x, 3) * a) + (pow(b, 2) * x)+ c * x + d;
        output << " |" << setfill('-') << setw(y + 100)
                       << "+\t" << "(" << x << ", " << y << ")"
                       << endl;
    }

    clrscr();
    cout << "\n\nPlease check the output file.\n\n";
    cout << "PRESS ANY KEY TO RETURN TO THE MENU";
    cin.ignore();
    cin.get();
    cout << endl;
    //goto main;
}

void deleteData(ofstream& output)
{
    output.close();  // CLOSES EXISTING FILE
    clrscr();
    output.open(filename.c_str(), ios::trunc);
    output.close();
    output.open(filename.c_str(), ios::app);
    clrscr();  //NEW FILE CREATED TO REPLACE OLD
    cout << "\n\n\n\n\n\n\n\n\t\t\t\tDATA CLEARED";
    cin.get();
    //goto main;
    // GETS USER INPUT AND PROCEEDS
}

//This program starts and executes so quickly that a load screen is completely
//unnecessary. It has been removed
/*void load()
 {
 clrscr();
 //int o, i; data localization: do not put data you only use in a loop
 //outside of the loop
 //gotoxy(33, 9);
 cout << "_________________";  //  TO
 //gotoxy(32, 10);
 cout << "/";  //PRINT
 //gotoxy(49, 10);
 cout << "/";  //BOX
 //gotoxy(35, 8);
 cout << "LOADING...";

 for (int o = 0; o < 3; o++)  // LOOP TO ANIMATE LOADING
 {
 //There was no reason to manually increment the x coordinate in gotoxy()
 //using a nested loop is also more efficient
 for (int x = 0; x < 50; x++)
 {
 for (int i = 0; i < 800; i++)
 {
 //gotoxy(x, 10);
 cout << "\f";
 }
 }
 }
 clrscr();
 }*/

//Exit screen is unnecessary
/*void exit()
 {
 clrscr();
 cout << "\n\n\n\n\n\n\n";
 cout << "\t\t\t\f\f\f\f\f\f \f\f\f       \f\f\f \f\f\f\f\f\f  \f\f\f\f\f\f  \n";
 cout << "\t\t\t\f\f\f\f\f\f  \f\f\f     \f\f\f    \f\f\f\f\f\f  \f\f\f\f\f\f \n";
 cout << "\t\t\t\f\f        \f\f\f   \f\f\f       \f\f      \f\f   \n";
 cout << "\t\t\t\f\f         \f\f\f \f\f\f        \f\f      \f\f   \n";
 cout << "\t\t\t\f\f\f\f\f\f      \f\f\f\f\f         \f\f      \f\f   \n";
 cout << "\t\t\t\f\f         \f\f\f \f\f\f        \f\f      \f\f   \n";
 cout << "\t\t\t\f\f        \f\f\f   \f\f\f       \f\f      \f\f   \n";
 cout << "\t\t\t\f\f\f\f\f\f   \f\f\f     \f\f\f    \f\f\f\f\f\f    \f\f   \n";
 cout << "\t\t\t\f\f\f\f\f\f  \f\f\f       \f\f\f   \f\f\f\f\f\f    \f\f   \n";
 cout << "\nžž.€°š°€žž.€°š°€žž.€°š°€žž.€°š°€žž.€°š°€žž.€°š°€žž.€°š°€žž.€°š°€žž.€°š°€žž.€°š°€";
 cout << "\n";
 for (int loop = 0; loop < 80; loop++)
 cout << "\f";
 cout << "\n\n\n\n\n\n\n\n\n\n\n\n\n\n";
 //cout << "\n\t\tPARTNERS\tBORLAND® C++\tMICROSOFT©";
 cout << "\n";
 for (int loop = 0; loop < 80; loop++)
 cout << "\f";
 cin.get();
 clrscr();
 }*/