My Experience in Programming

All but C#

matrix[r][c] return item at index at row r and col c

///////////////////////////////////////////////////////////
public static int[][] matr(int rr, int cc)
{
	int [][] mm= new int [rr][cc];
	int r, c;
	for(r=0; r<rr; r++)
	{
		System.out.printf("\n RRRRRRRRRRRRRRRRRRRRR |%d| #######################\n", r
		);
	for(c=0; c<cc; c++)
	{
		mm[r][c]=r*(rr+1)+c;
		System.out.printf("%d, ", mm[r][c]);

	}
	}
	return mm;
}

or just return array from Java method

return new int[]{year, month, day};

That's it To easy with Java ;-)

Java

int matrix[2][3] = { {1, 4, 2}, {3, 6, 8} };
int nrow= matrix.length;
int ncoll= matrix[0].length;
for(r=0; r<=nror; r++)
for(c=0; r<=ncol; c++)
System.out.printf("%d, ", matrix[[r][c])
); 
 

the simplest is the best the hardest to achieve

My MatLab Prog

xyz=12345 # 12345 not printed out
. . .

xyz # 42345 printed out

Plot

clear
x= 0:0.01: 2*pi;

figure

y_s =  sin(x);

y_c = cos (x );

plot(x, y_s, 'r*', x, y_c, 'b*'), grid; # grid for grid

title('Sin Cos') #title must be below plot ie naming after plotting
# set plot propeties like 

set(gca, 'linewidth', 4, 'fontsize', 22, 'fontweight', 'bold' )
# legend just put all plot in order, it auto to display properly in order

  h = legend ('sin', 'cos','location', 'NorthEastOutside'); #Follow order in plot
# NorthEastInside is default location , i.e if not using 'location' at all
 set (h, 'fontsize', 20, 'fontweight', 'bold');

pause( 2 ); # to keep OT open in 2secs for looking at plot

3-d mesh Plot

tx = ty = linspace (-8, 8, 41)';#'
[xx, yy] = meshgrid (tx, ty);
r = sqrt (xx .^ 2 + yy .^ 2) + eps;
tz = sin (r) ./ r;
mesh (tx, ty, tz), grid;
title('3D plot mesh');
set(gca, 'linewidth', 4, 'fontsize', 22, 'fontweight', 'bold' )

pause(22)

Array: Vector Matrix within [] idexed with () from 1 not 0

Print Out disp or fprintflike C printf with %c %d %f

FileIO

clear

x = 0:.1:1;
A = [x; exp(x)];

fileID = fopen('exp.txt','w');
fprintf(fileID,'%6s %12s\n','x','exp(x)');
fprintf(fileID,'%6.2f %12.8f\n',A);
fclose(fileID);

Elapsed Time with tic toc

Quite easily
tic
pause(1)
toc

Expense Sum

I frequently keep track my my expense on Amazon using my son Amzn card and put in M file to payback at ssa my_pay day
month start 
xx ={
1.234 % when what

2.345 % when what
3.456 % when what
];
sum(xx)

Statements

clear
x=5
if 0<x<10   # blk till elseif               
    y=4*x
elseif 10<x<40 # blk till else
    y = 10*x
else # blk till end
    y = 500
end
I

switch n
    case -1
        disp(n)
fprintf('case %d', n)

        disp('negative one')

    case 0
       disp(n)
fprintf('case %d', n)

    case 1
         disp(n)
fprintf('case %d', n)

    otherwise
        disp('other value')
end

clear

format long

pi # 3.141592653589793

format short with only 4 decimal digits

pi # ans = 3.1416

ML blk statement is from a statement to another or end

V=1:10;
V(end) #10
exit # exit right here for debugging purpose

Matrix Ops M [r,c]*M[c, n]

Dot Ops

lear
U=1:2;
 V=3:4;
 dot (U,V) # scalar 11=3*1+2*4=11dot prod of 2 vec
 U.*V 	   # Vector [3, 8=[1*3, 2*4] ele*ele

Function of single return y=abc(x, y, z) multi return [xx, yy]=abc(x, y, z) must ended with end Otherwise 2 func in the same file causing err of nested func

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


function y = ss (x, b, a)
% y = ss (x,b, a) Note order per usage l
ikelihood, x first incase only ss(x) b 2nd incase ss(x, b) a last as optional used or not use(a=1 
#if ss(a,x, b) then ss(x) causes err 'x' not found
#{
#}
switch (nargin)
    case 1
y= 1./(1.+exp(-x));
    return
    a=-1;
    b=0;
    
    case 2
    a=-1;
    otherwise
    a=-a;
    
end
x=a*(x-b);
y= 1./(1.+exp(x));
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

For

for n=1:10
disp(n)
end

  pause( 2 ); # to keep OT open in 2secs for looking at plot

My C Programming

ifndef MAIN_VV // included only once

#define MAIN_VV main // main_vv if not used this varies per diff file 
int MAIN_VV()
{
. . .
return 0;
} 
#endif

#include "fullpathto/_VV01.v" as  as usual with H file

.
.
.
int main()
{
.
.
.
}

 

Brief on some popular programming Language

Compile Language"C[Functional] C# Java[Objected Oriented]

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

  time_t tt= time(0);
  struct tm tm = *localtime(&tt);
  sprintf(STR, "%d/%02d/%02d @ %02d|%02d|%02d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);

Elapsed Time [ET]

Perl ET

 use Time::HiRes qw(usleep gettimeofday tv_interval);
   $t0 = [gettimeofday];
   sleep(1);
   $elapsed = 1000*tv_interval($t0);
   print"$elapsed mSec\n";

Bash ET

mS0=$(date +%s%N | cut -b1-13)
sleep 0.1
mS=$(date +%s%N | cut -b1-13)
(( et=mS - mS0 ))
echo "$et mSec"

Bash ET Sec even simpler just simply using $SECONDS

start=$SECONDS
sleep 1 # put some real task here instead of sleeping

duration=$(( SECONDS - start ))
echo "DURATION[$duration]"

Java ET

import java.util.*;
import java.lang.*;
import java.io.*;
import java.lang.Thread;


/* This is a simple Java program.
   FileName : "HelloWorld.java". */
public class ET01
{
	static long tt00=0;
////////////////////////////////////////////////////////
static int tt()
{
	//	static int y;
//	return ++y;
return 1;
}
////////////////////////////////////////////////////////
static void wait_mili(int nn)
{
	try
	{
				Thread.sleep(nn);
	}
		catch (Exception e)
		{
			}
} //wait_mili
////////////////////////////////////////////////////////


	///////////////////////////////////////////////////////////////////
	static	int NN=50;
	static int cnt=0;

	static long tt01;
	static int tic_mili()
	{
		tt01 = System.currentTimeMillis();
		int ett=(int)(tt01-tt00);
		tt00 = System.currentTimeMillis();
		return ett;

	}
	///////////////////////////////////////////////////////////////////

    // Your program begins with a call to main().
    // Prints "Hello, World" to the terminal window.
    public static void main(String args[])
    {
tic_mili();
wait_mili(NN);

int et=tic_mili();

			System.out.printf("<%d>wait_mili(%d)<%d>mSec\n", cnt, NN, et);
} // main
} // class

FileIO

#include <stdio.h>
 
int main()
{
   FILE *fp;
   char ch;
   char filename[33] = "d:/tmp/qik.txt";
   char *content = "This text is appeneded later to the file, using C programming.";

   /*  open for writing */
   
   printf("\nContents of %s  -\n\n", filename);
   

   fclose(fp);
   
   fp = fopen(filename, "a+");// appnd & read
   if(!fp)
   {
   printf("<<ERR>%s\n", "123456789\n", filename);
   }

   /* Write content to file */
   fprintf(fp, "%s\n", "qwertyuiop\n");

   fclose(fp);

   fp = fopen(filename, "r");
}

//////////////////////////////////////////////////////////////////////
#include <stdio.h>// printf
#include <stdlib.h> // malloc
#include <time.h>
//#include <time.h>
char * _sec2dt(time_t tt) // convert sec to datetime str yyy/mo/dd @hh|mi|se
{
	char *STR=(char *) malloc(55);
//	time_t tt= 1691177032;
  struct tm tm = *localtime(&tt);
  sprintf(STR, "%d/%02d/%02d @ %02d|%02d|%02d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
  return STR;

}
//////////////////////////////////////////////////////////////////////////
int main(int argc, char *argv[])
{
	int tt=time(0); // num of seconds Unix Epoch since midnight January 1st, 1970 at UTC
	char*dt=_sec2dt(tt);
	printf("|%s| %s %s [GCC-%s]\n",argv[0], __DATE__, __TIME__, __VERSION__);

	printf("DT{%s]\n", dt);
}

class Ex00

////////////////////////////////////////////////////////////////////////////////////////////////////////////

{

    static String Hello="Hello World";

    public void Ex00() // contrutor in case not static var

    {

//        System.out.printf("%s\n", Hello);

    }

///////////////////////////////////////////////////////////////////////////////////////////////

    public static void main(String[] args)

    {

        System.out.printf("%s\n", Hello);

//Ex00 ex00= new Ex00();

}

}

Script Language: Perl JavaScript MatLab

Brief on Text processing by some prog lang

single char

char c;

	while(c=fgetc(F_RD)!=EOF)
	{
		fputc(c, F_WR);
	}

multiple char

#define MAX 0x1000

char tmp[MAX]
;

	while(fgets(tmp, MAX, F_RD))
	{
//		strcat(STR, tmp);

		fputs(tmp, F_WR);
	}
}

$in_f = "${bf}.txt"; #  pd21-2 

$out_f = "_${bf}_01b.htm";

open(O_F, ">$out_f") ||

print"<ERR>>to make  $out_f \n";

open(IN_F, $in_f) ||

print"<ERR>>to GET  $in_f \n";

@AA00=<IN_F>;
print O_F $ss_htm; #string =array of char
close(O_F);

Time in C

#include <time.h>

struct tm{
int tm_sec;
int tm_min;
int tm_hour;
int tm_mday;
int tm_mon;
int tm_year;
int tm_wday;
int tm_yday;
int tm_isdst;
};

int tt=time(0);// save as drug taking
int diff= ime(0)-tt;
dd=sec/3600/24;//d
	hr=sec/3600; // hr
	sec-= hr*3600; //sec
	mi=sec/60; //mi
	Hr_Mi_Se[2]=se=sec-mi*60;

<<NP>> 1691122058}
char *ret=strchr(str, ' ');
int tt=atoi(ret);
int dif = time(0)-tt;==> Dy Hr Mi Se

har * _ss_DT(time_t tt)
{
	  struct tm *TT = localtime(&tt);
	  TT->tm_year+=1900;
	  TT->tm_mon+=1;

	char * str=(char *)malloc(55);
//void ST_VV(char *mm, struct tm *TT)
	sprintf(str, "%d/%d/%d @ %d|%d|%d", TT->tm_year, TT->tm_mon, TT->tm_mday,
	TT->tm_hour, TT->tm_min, TT->tm_sec);
	return str;
}

Brief on Math processing by some Prg Lang

Summary in cpmputing Pi with 2 billion terms of Atan using double IN C C++ C# JAVA

C Array

 #include <stdio.h>
 #include <stdlib.h>
 int * getArr()
 {
	 int * nn5=(int *)malloc(5*sizeof(int));
	 nn5[0]= 1;
	 nn5[1]= 2;
	 nn5[2]= 3;
	 nn5[3]= 4;
	 nn5[4]= 5;
	 return nn5;
 }
 int main()
 {
	 int i=0;
	 int *NN= getArr();// no need storage like int NN[5] as it already allocated in function
	 printf("[%d]= %d\n", i++, NN[i]);
	 printf("[%d]= %d\n", i++, NN[i]);
	 printf("[%d]= %d\n", i++, NN[i]);
	 printf("[%d]= %d\n", i++, NN[i]);
	 printf("[%d]= %d\n", i++, NN[i]);
 }

C# Array

using System;
namespace Hello
{
public class HelloWorld
{
static int [] getArr()
{
int [] Arr={-1, 3, 4, 5, 6};
return Arr;
}
//////////////////////////////////////////////////////////////////////////////////////////////////////

    public static void Main(string[] args)
    {
    int i=0;
    int [] B=getArr();
	Console.WriteLine ("{0}={1}", i, B[i]);
	Console.WriteLine ("{0}={1}", i++, B[i]);
	Console.WriteLine ("{0}={1}", i++, B[i]);
	Console.WriteLine ("{0}={1}", i++, B[i]);
	Console.WriteLine ("{0}={1}", i++, B[i]);
}
}
}

Java Array

public class Arr0
{

	///////////////////////////////////////////////////////////////////////////////////////////////
	static int[] getArr()
	{

	return new int[]{1, 2, 3, 4, 5};
	} // getArr
	///////////////////////////////////////////////////////////////////////////////////////////////

   public static void main(String[] args)

{
	int[] b=getArr();

		for(int i=0; i<b.length;i++)
	{
	System.out.printf("[%d ] %d\n", i, b[i]);

}
}
}

Java Script JS

function getArr()
{
return [u, vm x, y, z]; 
}

function getArr(x, y, z)
{
return [ q, w, e, r, t, y, u, i];
}

External JS

<script src="_xyz.jss"></script>

Internal

<html>
<head>
<title><title>
<style>
. . .
</style>

<script>
. . .
</script>
</head>
<body>

Perl

sub abc
{
	$str= @_[0]; // 1st arg
	$ln= @_[1];
	$new= @_[2];

abc 1 2 3 // passing args to sub abc

1. C progrm
2.