The Big Programming Thread - Page 144

On June 18 2012 14:15 sluggaslamoo wrote:




I agree, but there is an order in which you should learn paradigms which is why Pascal/C should be learned first, followed by Java/C#, followed by Javascript/Ruby/Lisp, followed by Haskell, etc.

You should learn the paradigms in this order.

Structured -> Object Oriented -> Imperative Functional -> Declarative Functional.

Going backwards is far more difficult and you will learn a lot slower and develop bad habits. Learning them in the order mentioned above will ensure that you have the best chance of having stronger fundamentals when learning programming.

For example, you need to know functional decomposition to do any language, but you only need to know object decomposition in OOP/FP. Learning Pascal first teaches functional decomposition because that's the primary skill required in structured programming.

Functional decomposition can be (and should be) applied to Java, but with Java there is a bigger focus on object decomposition, which can't be applied to Pascal. The catch is that object decomposition is a lot harder when you don't understand functional decomposition and you end up coming up with some really awkward designs. There is nothing more frustrating than seeing objects decomposed without a second thought applied to functional decomposition, because the developer who coded it started with Java.

So if you want to progress in the a way that ensures the best chance of being a solid programmer, you should follow the order mentioned above.

Not everybody learned it this way, and I'm sure there's some experts out there that started with Haskell. But just from my own experience I think this is the best way.

On June 21 2012 21:27 chiboni wrote:
Hi there,

I have following problem with java and reading bytes from an socket inputstream.

When I run the code, 2 bytes from the 6 bytes I want to read differ from the bytes I track with wireshark.
Java extends the bytes with an prefix 'ffffff' which negates them. This only occures on byte 2 and 3.

Does anyone have an idea how to solve this or what the problem is ?

code below

...
SomeFrame frame = new SomeFrame ();
byte[] readingHeader = new byte[6];
while((socketInStream.read(readingHeader,0,readingHeader.length))!=-1) {			
	System.out.println(Integer.toHexString(readingHeader[2]));
	System.out.println(Integer.toHexString(readingHeader[3]));
				
	frame.setHeader(readingHeader);		
	socketInStream.read(frame.data);
				
	//do something else ... 
			

The byte data type is an 8-bit signed two's complement integer. It has a minimum value of -128 and a maximum value of 127 (inclusive). The byte data type can be useful for saving memory in large arrays, where the memory savings actually matters. They can also be used in place of int where their limits help to clarify your code; the fact that a variable's range is limited can serve as a form of documentation.

On June 21 2012 22:04 MisterD wrote:


keep in mind, that a java byte is signed:



so the bytes you are looking for might just be
int byteValue = byte;
if(byteValue < 0) byteValue += 256
sysout(Integer.toHexString(byteValue);

On June 22 2012 00:55 ZpuX wrote:
Hiyo,

I wonder where to go from MATLAB.... From what I have heard MATLAB isn't really a programming language and it is mostly used for it's ability to handle values and matrix's. I knew some c++ from high school, or more like, I knew what the different loops did but I just couldn't understand the syntax and I had no real interest in learning it. But at uni we had an introduction course to MATLAB (engineering) where my friend helped me out a little bit in the beginning, and then everything just came quite easy from there. I wouldn't say I'm good at it, but if there is a problem I know where to search and I don't usually have any problems finding a solution.

Anyway, a lot of the jobs which I am looking at isn't really interested in MATLAB but want java, c etc, and I wonder if I will have any benefit from my previous skills in MATLAB and from where from where I should start? Which language resembles MATLAB the most and what kind of problems will I be looking at in the beginning?

On June 22 2012 06:12 ranshaked wrote:
I'm typing from my phone, so please bare with me. I had an assignment that I handed in that was not complete because I could not figure out how to do division. Basically the assignment is like this:
Randomly generate a math sign (+*/-) and two random numbers and ask the user to solve the problem. Everything works properly except the division. I know that it is because I'm using integers, but when I caste them as floats in my if or switch statements (tried both) it either gets 0.000000 all the time or it messes up the other integers. The final line needs to print the answer. Because it is random, I'm struggling with the final answer, everything will wok except division

I'll post the code later. Thanks

#include <stdio.h>
#include <stdlib.h>
#include <time.h>

int main(int argc, char *argv[])
{
  int randomNum = 0, randomNum2 = 0, mathOperator = 0;
  float result = 0, answer = 0;
  srand ( time(NULL) );
  
  char map[4] = {'-','+','*','/'};
  
  while( 1 )
  {
      randomNum = rand()%100; //Truncated it to a limit of 100, so that you don't get ridiculous numbers...
      printf("%i ",randomNum);
      mathOperator = rand()%4; 
      printf("%c ",map[mathOperator] );
      randomNum2 = rand()%100;
      printf("%i",randomNum2);
      
      switch ( map[mathOperator] )
      {
             case '-':
                  result = randomNum - randomNum2;
                  break;
             case '+':
                  result = randomNum + randomNum2;
                  break;
             case '*':
                  result = randomNum * randomNum2;
                  break;
             case '/':
                  result = (float)randomNum / ( (float)randomNum2 );
                  printf(" Result is: %f ",result);
                  break;
      }
      
      //How come the divison never works??
      //It's because of round-off errors within the computer. Trying looking at:
     //http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm
      printf(" \nWhat is the answer? ");
      scanf("%f",&answer);
      printf("you entered: %f \n",answer);
      fflush(stdin);
      
      if ( answer == result )
         printf("Correct! \n");
  }
  
  return 0;
}