Solution of the Fermi-Thomas Potential Energy Equation for Zero Temperature and without Exchange by James Pate Williams, Jr.

More Results from the 1953 Metropolis Among Others Technical Report © Tuesday, February 25, 2025, by James Pate Williams, Jr.

Reproduction and Extension of Metropolis Among Others Results in Their 1953 Technical Report (c) February 22, 2025, by James Pate Williams, Jr.

Blog Entry © Thursday, February 13, 2025, by James Pate Williams, Jr. Comparison of Several C/C++ Sorting Algorithms in a Homemade Dynamic Link Library (DLL)

Blog Entry © Friday, January 24, 2025, by James Pate Williams, Jr. Graphs and Tables of the Fresnel Cosine and Sine Integrals

Blog Entry © Thursday, January 23, 2025, by James Pate Williams, Jr. Fresnel Integral Tables and Source Code

Fresnel Cosine Integral

x C(x) Lau C(x) NBS % Difference
-0.620000 -0.5977736837 -0.5970137789 0.1272033494
-0.570400 -0.5556807496 -0.5553215257 0.0646666400
-0.520800 -0.5114255691 -0.5112670118 0.0310078114
-0.471200 -0.4655007132 -0.4654362526 0.0138485424
-0.421600 -0.4183252709 -0.4183015697 0.0056659009
-0.372000 -0.3702461017 -0.3702384156 0.0020759626
-0.322400 -0.3215416213 -0.3215395006 0.0006595409
-0.272800 -0.2724274481 -0.2724269764 0.0001731156
-0.223200 -0.2230633569 -0.2230632794 0.0000347412
-0.173600 -0.1735611006 -0.1735610925 0.0000046509
-0.124000 -0.1239927667 -0.1239927663 0.0000003151
-0.074400 -0.0743994375 -0.0743994375 0.0000000053
-0.024800 -0.0247999977 -0.0247999977 0.0000000000
0.024800 0.0247999977 0.0247999977 0.0000000000
0.074400 0.0743994375 0.0743994375 0.0000000053
0.124000 0.1239927667 0.1239927663 0.0000003151
0.173600 0.1735611006 0.1735610925 0.0000046509
0.223200 0.2230633569 0.2230632794 0.0000347412
0.272800 0.2724274481 0.2724269764 0.0001731156
0.322400 0.3215416213 0.3215395006 0.0006595409
0.372000 0.3702461017 0.3702384156 0.0020759626
0.421600 0.4183252709 0.4183015697 0.0056659009
0.471200 0.4655007132 0.4654362526 0.0138485424
0.520800 0.5114255691 0.5112670118 0.0310078114
0.570400 0.5556807496 0.5553215257 0.0646666400
0.620000 0.5977736837 0.5970137789 0.1272033494

Fresnel Sine Integral

x S(x) Lau S(x) Integral % Difference
-0.6200000000 -0.1215759428 -0.1215759428 0.0000000000
-0.5704000000 -0.0953732384 -0.0953732384 0.0000000000
-0.5208000000 -0.0730090407 -0.0730090407 0.0000000000
-0.4712000000 -0.0543049498 -0.0543049498 0.0000000000
-0.4216000000 -0.0390194784 -0.0390194784 0.0000000000
-0.3720000000 -0.0268634258 -0.0268634258 0.0000000000
-0.3224000000 -0.0175128445 -0.0175128445 0.0000000000
-0.2728000000 -0.0106195909 -0.0106195909 0.0000000000
-0.2232000000 -0.0058195744 -0.0058195744 0.0000000000
-0.1736000000 -0.0027389132 -0.0027389132 0.0000000000
-0.1240000000 -0.0009982644 -0.0009982644 0.0000000000
-0.0744000000 -0.0002156329 -0.0002156329 0.0000000000
-0.0248000000 -0.0000079864 -0.0000079864 0.0000000000
0.0248000000 0.0000079864 0.0000079864 0.0000000000
0.0744000000 0.0002156329 0.0002156329 0.0000000000
0.1240000000 0.0009982644 0.0009982644 0.0000000000
0.1736000000 0.0027389132 0.0027389132 0.0000000000
0.2232000000 0.0058195744 0.0058195744 0.0000000000
0.2728000000 0.0106195909 0.0106195909 0.0000000000
0.3224000000 0.0175128445 0.0175128445 0.0000000000
0.3720000000 0.0268634258 0.0268634258 0.0000000000
0.4216000000 0.0390194784 0.0390194784 0.0000000000
0.4712000000 0.0543049498 0.0543049498 0.0000000000
0.5208000000 0.0730090407 0.0730090407 0.0000000000
0.5704000000 0.0953732384 0.0953732384 0.0000000000
0.6200000000 0.1215759428 0.1215759428 0.0000000000

// FresnelFunctions.cpp : Defines the entry point for the application.
// (c) Thursday, January 23, 2025, by James Pate Williams, Jr.
// Tables of Fresnel Integrals C(x) and S(x)
// References: "A Numerical Library in C for Scientists and Engineers"
// (c) 1995 by H. T. Lau also the National Bureau of Standards and
// https://nvlpubs.nist.gov/nistpubs/jres/102/3/j23mie.pdf
// https://digital.library.unt.edu/ark:/67531/metadc40301/m2/1/high_res_d/applmathser55_w.pdf

#include "framework.h"
#include "FresnelFunctions.h"
#include <chrono>
#include <cwchar>
#include <vector>

#define MAX_LOADSTRING 100

// resource definitions

#define IDC_EDIT1 201
#define IDC_EDIT2 202
#define IDC_EDIT3 203
#define IDC_EDIT4 204
#define IDC_EDIT5 205

#define IDC_STATIC1 301
#define IDC_STATIC2 302
#define IDC_STATIC3 303
#define IDC_STATIC4 304

#define IDC_BUTTON_COMPUTE 401
#define IDC_BUTTON_CLEAR 402

// Global Variables:

HINSTANCE hInst;                                // current instance
WCHAR szTitle[MAX_LOADSTRING];                  // The title bar text
WCHAR szWindowClass[MAX_LOADSTRING];            // the main window class name
WCHAR buffer[16834], line[128];

// Forward declarations of functions included in this code module:

ATOM                MyRegisterClass(HINSTANCE hInstance);
BOOL                InitInstance(HINSTANCE, int);
LRESULT CALLBACK    WndProc(HWND, UINT, WPARAM, LPARAM);
INT_PTR CALLBACK    About(HWND, UINT, WPARAM, LPARAM);

int APIENTRY wWinMain(_In_ HINSTANCE hInstance,
                     _In_opt_ HINSTANCE hPrevInstance,
                     _In_ LPWSTR    lpCmdLine,
                     _In_ int       nCmdShow)
{
    UNREFERENCED_PARAMETER(hPrevInstance);
    UNREFERENCED_PARAMETER(lpCmdLine);

    // TODO: Place code here.

    // Initialize global strings

    LoadStringW(hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING);
    LoadStringW(hInstance, IDC_FRESNELFUNCTIONS, szWindowClass, MAX_LOADSTRING);
    MyRegisterClass(hInstance);

    // Perform application initialization:

    if (!InitInstance (hInstance, nCmdShow))
    {
        return FALSE;
    }

    HACCEL hAccelTable = LoadAccelerators(hInstance, MAKEINTRESOURCE(IDC_FRESNELFUNCTIONS));

    MSG msg;

    // Main message loop:

    while (GetMessage(&msg, nullptr, 0, 0))
    {
        if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg))
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }

    return (int) msg.wParam;
}
//
//  FUNCTION: MyRegisterClass()
//
//  PURPOSE: Registers the window class.
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
    WNDCLASSEXW wcex = { };

    wcex.cbSize = sizeof(WNDCLASSEX);

    wcex.style          = CS_HREDRAW | CS_VREDRAW;
    wcex.lpfnWndProc    = WndProc;
    wcex.cbClsExtra     = 0;
    wcex.cbWndExtra     = 0;
    wcex.hInstance      = hInstance;
    wcex.hIcon          = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_FRESNELFUNCTIONS));
    wcex.hCursor        = LoadCursor(nullptr, IDC_ARROW);
    wcex.hbrBackground  = (HBRUSH)(COLOR_WINDOW+1);
    wcex.lpszMenuName   = MAKEINTRESOURCEW(IDC_FRESNELFUNCTIONS);
    wcex.lpszClassName  = szWindowClass;
    wcex.hIconSm        = LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

    return RegisterClassExW(&wcex);
}
//
//   FUNCTION: InitInstance(HINSTANCE, int)
//
//   PURPOSE: Saves instance handle and creates main window
//
//   COMMENTS:
//
//        In this function, we save the instance handle in a global variable and
//        create and display the main program window.
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   hInst = hInstance; // Store instance handle in our global variable

   HWND hWnd = CreateWindowW(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, nullptr, nullptr, hInstance, nullptr);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

void fg_lau(double, double*, double*);

void fresnel_lau(double x, double* c, double* s)
{
	double absx, x3, x4, a, p, q, f, g, c1, s1;

	absx = fabs(x);
	if (absx <= 1.2) {
		a = x * x;
		x3 = a * x;
		x4 = a * a;
		p = (((5.47711385682687e-6 * x4 - 5.28079651372623e-4) * x4 +
			1.76193952543491e-2) * x4 - 1.99460898826184e-1) * x4 + 1.0;
		q = (((1.18938901422876e-7 * x4 + 1.55237885276994e-5) * x4 +
			1.09957215025642e-3) * x4 + 4.72792112010453e-2) * x4 + 1.0;
		*c = x * p / q;
		p = (((6.71748466625141e-7 * x4 - 8.45557284352777e-5) * x4 +
			3.87782123463683e-3) * x4 - 7.07489915144523e-2) * x4 +
			5.23598775598299e-1;
		q = (((5.95281227678410e-8 * x4 + 9.62690875939034e-6) * x4 +
			8.17091942152134e-4) * x4 + 4.11223151142384e-2) * x4 + 1.0;
		*s = x3 * p / q;
	}
	else if (absx <= 1.6) {
		a = x * x;
		x3 = a * x;
		x4 = a * a;
		p = ((((-5.68293310121871e-8 * x4 + 1.02365435056106e-5) * x4 -
			6.71376034694922e-4) * x4 + 1.91870279431747e-2) * x4 -
			2.07073360335324e-1) * x4 + 1.00000000000111e0;
		q = ((((4.41701374065010e-10 * x4 + 8.77945377892369e-8) * x4 +
			1.01344630866749e-5) * x4 + 7.88905245052360e-4) * x4 +
			3.96667496952323e-2) * x4 + 1.0;
		*c = x * p / q;
		p = ((((-5.76765815593089e-9 * x4 + 1.28531043742725e-6) * x4 -
			1.09540023911435e-4) * x4 + 4.30730526504367e-3) * x4 -
			7.37766914010191e-2) * x4 + 5.23598775598344e-1;
		q = ((((2.05539124458580e-10 * x4 + 5.03090581246612e-8) * x4 +
			6.87086265718620e-6) * x4 + 6.18224620195473e-4) * x4 +
			3.53398342767472e-2) * x4 + 1.0;
		*s = x3 * p / q;
	}
	else if (absx < 1.0e15) {
		fg_lau(x, &f, &g);
		a = x * x;
		a = (a - floor(a / 4.0) * 4.0) * 1.57079632679490;
		c1 = cos(a);
		s1 = sin(a);
		a = (x < 0.0) ? -0.5 : 0.5;
		*c = f * s1 - g * c1 + a;
		*s = -f * c1 - g * s1 + a;
	}
	else
		*c = *s = ((x > 0.0) ? 0.5 : -0.5);
}

void fg_lau(double x, double* f, double* g)
{
	double absx, c, s, c1, s1, a, xinv, x3inv, c4, p, q;

	absx = fabs(x);
	if (absx <= 1.6) {
		fresnel_lau(x, &c, &s);
		a = x * x * 1.57079632679490;
		c1 = cos(a);
		s1 = sin(a);
		a = (x < 0.0) ? -0.5 : 0.5;
		p = a - c;
		q = a - s;
		*f = q * c1 - p * s1;
		*g = p * c1 + q * s1;
	}
	else if (absx <= 1.9) {
		xinv = 1.0 / x;
		a = xinv * xinv;
		x3inv = a * xinv;
		c4 = a * a;
		p = (((1.35304235540388e1 * c4 + 6.98534261601021e1) * c4 +
			4.80340655577925e1) * c4 + 8.03588122803942e0) * c4 +
			3.18309268504906e-1;
		q = (((6.55630640083916e1 * c4 + 2.49561993805172e2) * c4 +
			1.57611005580123e2) * c4 + 2.55491618435795e1) * c4 + 1.0;
		*f = xinv * p / q;
		p = ((((2.05421432498501e1 * c4 + 1.96232037971663e2) * c4 +
			1.99182818678903e2) * c4 + 5.31122813480989e1) * c4 +
			4.44533827550512e0) * c4 + 1.01320618810275e-1;
		q = ((((1.01379483396003e3 * c4 + 3.48112147856545e3) * c4 +
			2.54473133181822e3) * c4 + 5.83590575716429e2) * c4 +
			4.53925019673689e1) * c4 + 1.0;
		*g = x3inv * p / q;
	}
	else if (absx <= 2.4) {
		xinv = 1.0 / x;
		a = xinv * xinv;
		x3inv = a * xinv;
		c4 = a * a;
		p = ((((7.17703249365140e2 * c4 + 3.09145161574430e3) * c4 +
			1.93007640786716e3) * c4 + 3.39837134926984e2) * c4 +
			1.95883941021969e1) * c4 + 3.18309881822017e-1;
		q = ((((3.36121699180551e3 * c4 + 1.09334248988809e4) * c4 +
			6.33747155851144e3) * c4 + 1.08535067500650e3) * c4 +
			6.18427138172887e1) * c4 + 1.0;
		*f = xinv * p / q;
		p = ((((3.13330163068756e2 * c4 + 1.59268006085354e3) * c4 +
			9.08311749529594e2) * c4 + 1.40959617911316e2) * c4 +
			7.11205001789783e0) * c4 + 1.01321161761805e-1;
		q = ((((1.15149832376261e4 * c4 + 2.41315567213370e4) * c4 +
			1.06729678030581e4) * c4 + 1.49051922797329e3) * c4 +
			7.17128596939302e1) * c4 + 1.0;
		*g = x3inv * p / q;
	}
	else {
		xinv = 1.0 / x;
		a = xinv * xinv;
		x3inv = a * xinv;
		c4 = a * a;
		p = ((((2.61294753225142e4 * c4 + 6.13547113614700e4) * c4 +
			1.34922028171857e4) * c4 + 8.16343401784375e2) * c4 +
			1.64797712841246e1) * c4 + 9.67546032967090e-2;
		q = ((((1.37012364817226e6 * c4 + 1.00105478900791e6) * c4 +
			1.65946462621853e5) * c4 + 9.01827596231524e3) * c4 +
			1.73871690673649e2) * c4 + 1.0;
		*f = (c4 * (-p) / q + 0.318309886183791) * xinv;
		p = (((((1.72590224654837e6 * c4 + 6.66907061668636e6) * c4 +
			1.77758950838030e6) * c4 + 1.35678867813756e5) * c4 +
			3.87754141746378e3) * c4 + 4.31710157823358e1) * c4 +
			1.53989733819769e-1;
		q = (((((1.40622441123580e8 * c4 + 9.38695862531635e7) * c4 +
			1.62095600500232e7) * c4 + 1.02878693056688e6) * c4 +
			2.69183180396243e4) * c4 + 2.86733194975899e2) * c4 + 1.0;
		*g = (c4 * (-p) / q + 0.101321183642338) * x3inv;
	}
}

double S(double z)
{
	int n = 768;
	double a = 0.0;
	double b = z;
	double h = (b - a) / n;
	double h2 = 2.0 * h;
	double s = 0.0;
	double t = 0.0;
	double x = a + h;
	double pi = 4.0 * atan(1.0);
	
	for (int i = 1; i < n; i += 2)
	{
		s += sin(pi * x * x / 2.0);
		x += h2;
	}

	x = a + h2;

	for (int i = 2; i < n; i += 2)
	{
		t += sin(pi * x * x / 2.0);
		x += h2;
	}

	double endA = 0.0;
	double endB = sin(pi * z * z / 2.0);
	return h * (endA + 4 * s + 2 * t + endB) / 3.0;
}

void fresnel_nbs(double x, double* c, double* s)
{
	double pi = 4.0 * atan(1.0);

	*c = x - pi * pi * pow(x, 5.0) / 40.0 -
		pi * pi * pi * pi * pow(x, 9.0) / 3456.0;
	// the following computation is in error
	*s = -pi / 6.0 + pi * pi * pi * pow(x, 7.0) / 336.0 -
		pow(pi, 5.0) * pow(x, 11.0) / 42240.0;
	// resort to Simpson's Rule with n = 16384
	*s = S(x);
} 

//
//  FUNCTION: WndProc(HWND, UINT, WPARAM, LPARAM)
//
//  PURPOSE: Processes messages for the main window.
//
//  WM_COMMAND  - process the application menu
//  WM_PAINT    - Paint the main window
//  WM_DESTROY  - post a quit message and return
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	double lt = 0.0, rt = 0.0;
	int cors = 1, nPts = 0;
	WCHAR* endPt;
	static HWND hwndEdit1 = 0, hwndEdit2 = 0;
	static HWND hwndEdit3 = 0, hwndEdit4 = 0, hwndEdit5 = 0;

	switch (message)
	{
	case WM_CREATE:
	{
		CreateWindowEx(0, L"STATIC", L"Lt Point:", WS_CHILD | WS_VISIBLE,
			10, 10, 80, 20, hWnd, (HMENU)IDC_STATIC1, GetModuleHandle(NULL), NULL);
		CreateWindowEx(0, L"STATIC", L"Rt Point:", WS_CHILD | WS_VISIBLE,
			10, 40, 80, 20, hWnd, (HMENU)IDC_STATIC2, GetModuleHandle(NULL), NULL);
		CreateWindowEx(0, L"STATIC", L"n Points:", WS_CHILD | WS_VISIBLE,
			10, 70, 80, 20, hWnd, (HMENU)IDC_STATIC3, GetModuleHandle(NULL), NULL);
		CreateWindowEx(0, L"STATIC", L"C 1, S, 2:", WS_CHILD | WS_VISIBLE,
			10, 100, 80, 20, hWnd, (HMENU)IDC_STATIC4, GetModuleHandle(NULL), NULL);

		hwndEdit1 = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER,
			100, 10, 200, 20, hWnd, (HMENU)IDC_EDIT1, GetModuleHandle(NULL), NULL);
		hwndEdit2 = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER,
			100, 40, 200, 20, hWnd, (HMENU)IDC_EDIT2, GetModuleHandle(NULL), NULL);
		hwndEdit3 = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER,
			100, 70, 200, 20, hWnd, (HMENU)IDC_EDIT3, GetModuleHandle(NULL), NULL);
		hwndEdit4 = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER,
			100, 100, 200, 20, hWnd, (HMENU)IDC_EDIT4, GetModuleHandle(NULL), NULL);
		hwndEdit5 = CreateWindowEx(0, L"EDIT", NULL, WS_CHILD | WS_VISIBLE | WS_BORDER
			| ES_MULTILINE, 100, 170, 400, 400, hWnd, (HMENU)IDC_EDIT5,
			GetModuleHandle(NULL), NULL);

		CreateWindowEx(0, L"BUTTON", L"Compute", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
			10, 130, 80, 30, hWnd, (HMENU)IDC_BUTTON_COMPUTE, GetModuleHandle(NULL), NULL);
		CreateWindowEx(0, L"BUTTON", L"Clear", WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
			220, 130, 80, 30, hWnd, (HMENU)IDC_BUTTON_CLEAR, GetModuleHandle(NULL), NULL);

		SetDlgItemText(hWnd, IDC_EDIT1, L"-0.62");
		SetDlgItemText(hWnd, IDC_EDIT2, L"+0.62");
		SetDlgItemText(hWnd, IDC_EDIT3, L"25");
		SetDlgItemText(hWnd, IDC_EDIT4, L"1");
	}
    case WM_COMMAND:
        {
            int wmId = LOWORD(wParam);

            // Parse the menu selections:
			
			switch (wmId)
			{
			case IDC_BUTTON_COMPUTE:
			{
				buffer[0] = { '/0' };
				GetWindowText(hwndEdit1, line, 127);
				lt = wcstod(line, &endPt);

				if (!(lt >= -0.62 && lt <= 0.50))
				{
					MessageBox(hWnd, L"Must be -0.62 <= lt <= 0.50", L"Warning",
						MB_OK | MB_ICONWARNING);
					return 0;
				}

				GetWindowText(hwndEdit2, line, 127);
				rt = wcstod(line, &endPt);

				if (!(rt >= 0.51 && rt <= 0.62))
				{
					MessageBox(hWnd, L"Must be 0.51 <= rt <= 0.62", L"Warning",
						MB_OK | MB_ICONWARNING);
					return 0;
				}

				nPts = GetDlgItemInt(hWnd, IDC_EDIT3, FALSE, FALSE);

				if (nPts < 1 || nPts > 25)
				{
					MessageBox(hWnd, L"n-points must be >= 1 & <= 25", L"Warning",
						MB_OK | MB_ICONWARNING);
					return 0;
				}

				cors = GetDlgItemInt(hWnd, IDC_EDIT4, FALSE, FALSE);

				if (!(cors == 1 || cors == 2))
				{
					MessageBox(hWnd, L"C(x) = 1 or S(x) = 2", L"Warning",
						MB_OK | MB_ICONWARNING);
					return 0;
				}

				if (cors == 1)
				{
					wsprintf(line, L"Fresnel Cosine Integral\r\n\r\n");
					wcscpy_s(buffer, 16383, line);
					wsprintf(line, L"x\t\tC(x) Lau\t\tC(x) NBS\t\t%% Difference\r\n");
					wcscat_s(buffer, 16383, line);
				}

				else if (cors == 2)
				{
					wsprintf(line, L"Fresnel Sine Integral\r\n\r\n");
					wcscpy_s(buffer, 16383, line);
					wsprintf(line, L"x\t\tS(x) Lau\t\tS(x) Integral\t%% Difference\r\n");
					wcscat_s(buffer, 16383, line);
				}

				double deltaX = (rt - lt) / nPts, x = lt;

				for (int i = 0; i <= nPts; i++)
				{
					double c1 = 0.0, c2 = 0.0, s1 = 0.0, s2 = 0.0;
					double percentDifference = 0.0;
					double cx = x, sx = x;

					fresnel_lau(cx, &c1, &s1);
					fresnel_nbs(sx, &c2, &s2);

					if (cors == 1)
					{
						percentDifference = fabs(c1 - c2) / fabs((c1 + c2) / 2.0);
						swprintf_s(
							line, L"%13.6lf\t%13.10lf\t%13.10lf\t%13.10lf\r\n",
							cx, c1, c2, 100.0 * percentDifference);
						wcscat_s(buffer, 16383, line);
					}

					else if (cors == 2)
					{
						percentDifference = fabs(s1 - s2) / fabs((s1 + s2) / 2.0);
						swprintf_s(
							line, L"%13.10lf\t%13.10lf\t%13.10lf\t%13.10lf\r\n",
							sx, s1, s2, 100.0 * percentDifference);
						wcscat_s(buffer, 16383, line);
					}

					x += deltaX;
				}

				SetDlgItemText(hWnd, IDC_EDIT5, buffer);
			}
			break;
			case IDC_BUTTON_CLEAR:
			{
				wcscpy_s(buffer, 16383, L"\0");
				SetDlgItemText(hWnd, IDC_EDIT5, buffer);
			}
			break;
            case IDM_ABOUT:
                DialogBox(hInst, MAKEINTRESOURCE(IDD_ABOUTBOX), hWnd, About);
                break;
            case IDM_EXIT:
                DestroyWindow(hWnd);
                break;
            default:
                return DefWindowProc(hWnd, message, wParam, lParam);
            }
        }
        break;
    case WM_PAINT:
        {
            PAINTSTRUCT ps;
            HDC hdc = BeginPaint(hWnd, &ps);
            // TODO: Add any drawing code that uses hdc here...
            EndPaint(hWnd, &ps);
        }
        break;
	case WM_SIZE:
		if (hwndEdit5)
		{
			RECT rcClient;
			GetClientRect(hWnd, &rcClient);
			SetWindowPos(hwndEdit5, NULL, 10, 170, rcClient.right - 20,
				rcClient.bottom - 20, SWP_NOZORDER);
		}
		break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }
    return 0;
}

// Message handler for about box.
INT_PTR CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
    UNREFERENCED_PARAMETER(lParam);
    switch (message)
    {
    case WM_INITDIALOG:
        return (INT_PTR)TRUE;

    case WM_COMMAND:
        if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL)
        {
            EndDialog(hDlg, LOWORD(wParam));
            return (INT_PTR)TRUE;
        }
        break;
    }
    return (INT_PTR)FALSE;
}

Blog Entry © Thursday, January 23, 2025, by James Pate Williams, Jr. Ackermann’s Super-Exponential Recursive Function in Vanilla C Programming Language

i = 2
j = 1
a(2, 1) =
4
# decimal digits = 1
enter another set (n to quit)? y
i = 2
j = 2
a(2, 2) =
16
# decimal digits = 2
enter another set (n to quit)? y
i = 2
j = 3
a(2, 3) =
65536
# decimal digits = 5
enter another set (n to quit)? y
i = 2
j = 4
a(2, 4) =
200352993040684646497907235156025575044782547556975141926501697371089\
405955631145308950613088093334810103823434290726318182294938211881266886\
950636476154702916504187191635158796634721944293092798208430910485599057\
015931895963952486337236720300291696959215610876494888925409080591145703\
767520850020667156370236612635974714480711177481588091413574272096719015\
183628256061809145885269982614142503012339110827360384376787644904320596\
037912449090570756031403507616256247603186379312648470374378295497561377\
098160461441330869211810248595915238019533103029216280016056867010565164\
...
506264233788565146467060429856478196846159366328895429978072254226479040\
061601975197500746054515006029180663827149701611098795133663377137843441\
619405312144529185518013657555866761501937302969193207612000925506508158\
327550849934076879725236998702356793102680413674571895664143185267905471\
716996299036301554564509004480278905570196832831363071899769915316667920\
895876857229060091547291963638167359667395997571032601557192023734858052\
112811745861006515259888384311451189488055212914577569914657753004138471\
712457796504817585639507289533753975582208777750607233944558789590571915\
6736
# decimal digits = 19729
enter another set (n to quit)?
/* 
** Computation of Akermann's super
** exponential function by James
** Pate Williams, Jr. (c) Tuesday,
** August 27, 2024 lip version
*/

#include <stdio.h>
#include "lip.h"

verylong Ackermann(verylong zi, verylong zj) {
	verylong a = 0;
	if (zscompare(zi, 1) == 0) {
		verylong ztwo = 0;
		zintoz(2, &ztwo);
		zexp(ztwo, zj, &a);
		return a;
	}
	else if (zscompare(zj, 1) == 0)
	{
		verylong ztwo = 0, ziminus1 = 0;
		zintoz(2, &ztwo);
		zsadd(zi, -1, &ziminus1);
		return Ackermann(ziminus1, ztwo);
	}
	else if (
		zscompare(zi, 2) >= 0 &&
		zscompare(zj, 2) >= 0) {
		verylong ziminus1 = 0;
		verylong zjminus1 = 0;
		verylong temp = 0;
		zsadd(zi, -1, &ziminus1);
		zsadd(zj, -1, &zjminus1);
		if (zscompare(ziminus1, 1) >= 0 &&
			zscompare(zjminus1, 1) >= 0) {
			return
				Ackermann(ziminus1, Ackermann(zi, zjminus1));
		}
	}
	return 0;
}

int DigitCount(verylong za) {
	int count = 0;
	while (zscompare(za, 0) > 0) {
		zsdiv(za, 10, &za);
		count++;
	}
	return count;
}

int main(void) {
	for (;;) {
		char buffer[256] = { '\0' };
		int i = 0, j = 0, number = 0;
		verylong za = 0, zi = 0, zj = 0;
		buffer[0] = '\0';
		printf_s("i = ");
		scanf_s("%d", &i);
		printf_s("j = ");
		scanf_s("%d", &j);
		zintoz(i, &zi);
		zintoz(j, &zj);
		printf_s("a(%d, %d) = \n", i, j);
		za = Ackermann(zi, zj);
		zwriteln(za);
		number = DigitCount(za);
		printf_s("# decimal digits = %d\n",
			number);
		printf_s("enter another set (n to quit)? ");
		scanf_s("%s", buffer, sizeof(buffer));
		zfree(&za);
		if (buffer[0] == 'n')
			break;
	}
	return 0;
}