C bitwise programming

Question

Can I please work with some bitwise, and if abbreviated? I commented on what I thought.

//Bitwise AND not sure how it decides 32 or 0, then set board[i]    
board[i] = (randNum & 1024) ? 32 : 0;

//it the j variable j in the neighborOffset array, then mods it by 2048
//then takes that variable from the board array, then shifts 1 to 32
//then bitwise and of those 2 variables.
if(board[(i + neighborOffset[j]) % 2048] & (1 << 5))

//Not sure about this one. Can someone please explain it? 
board[i] |= ((board[i] ^ 34) && (board[i] ^ 35)) ? ( (board[i]^3) ? 0 : (1<<4)) : (1<<4);

//Not sure how it decides if it uses 'X' or ' '
putchar(board[i] ? 'X':' ');

-----------------------------------------------

I get it.

    putchar(board[i] ? 'X':' ');

#include <stdio.h>
#include <unistd.h>
#include <time.h>
#include <signal.h>
#include <stdlib.h>
//#include <dos.h>


int main()
{
    int board[2048] = {0};
    board[0] = 5;
    board[1] = 9;
    board[2] = 0;
    board[3] = 2;

    putchar(board[0] ? 'X':' ');
    putchar(board[1] ? 'X':' ');
    putchar(board[2] ? 'X':' ');
    putchar(board[3] ? 'X':' ');
    printf(" \n");
    return (0);

}

Output

XX X 

Reason for success putchar returns 1. http://www.cplusplus.com/reference/cstdio/putchar/

Answer 1

Not sure about that. Can someone explain this?

board[i] |= ((board[i] ^ 34) && (board[i] ^ 35)) ? ( (board[i]^3) ? 0 : (1<<4)) : (1<<4);

Do not ask for fish, ask how to catch fish. Instead of explaining this to you, let me teach you how to explain it to you.

I don't understand this crazy code anymore than you are doing right now, so I'm going to write down a process that I will use to understand this code.

We begin to understand this by first reformatting it so that the indentation gives us the key:

board[i] |= 
    ((board[i] ^ 34) && (board[i] ^ 35)) ? 
        ((board[i]^3) ? 
            0 : 
            (1<<4)) : 
        (1<<4);

, . , .

int original = board[i];
int result =  
    ((original ^ 34) && (original ^ 35)) ? 
        ((original ^ 3) ? 
            0 : 
            (1<<4)) : 
        (1<<4);
board[i] = original | result;

. , .

int original = board[i];
int result;
if ((original ^ 34) && (original ^ 35))
{
    if (original ^ 3)
        result = 0;
    else
        result = 1 << 4;
}
else
    result = 1 << 4;

board[i] = original | result;

, , "if" : , , , ? .

int original = board[i];
int result;
if ((original ^ 34) && (original ^ 35) && (original ^ 3))
    result = 0;
else
    result = 1 << 4;
board[i] = original | result;

, . .

(original ^ 34) && ...

? , , , .

int original = board[i];
int result;
int condition34 = (original ^ 34) != 0;
int condition35 = (original ^ 35) != 0;
int condition3 = (original ^ 3) != 0;
if (condition34 && condition35 && condition3)
    result = 0;
else
    result = 1 << 4;
board[i] = original | result;

, : " (x ^ y) != 0, , ? x^y 0. x^y , x y . x y ? . , , , , . :

int original = board[i];
int result;
int condition34 = (original != 34);
int condition35 = (original != 35);
int condition3 = (original != 3);
if (condition34 && condition35 && condition3)
    result = 0;
else
    result = 1 << 4;
board[i] = original | result;

- . board[i]. result , original|result no-op. , result 16. , , result:

int original = board[i];
int condition34 = (original != 34);
int condition35 = (original != 35);
int condition3 = (original != 3);
if (condition34 && condition35 && condition3)
{ /* do nothing */ }
else
   board[i] = original | 16;

, if " ":

int original = board[i];
int condition34 = (original != 34);
int condition35 = (original != 35);
int condition3 = (original != 3);
if (!(condition34 && condition35 && condition3))
   board[i] = original | 16;

,

!(a && b)

- ,

!a || !b

:

int original = board[i];
int condition34 = (original != 34);
int condition35 = (original != 35);
int condition3 = (original != 3);
if ((!condition34) || (!condition35) || (!condition3))
   board[i] = original | 16;

-, . .

int original = board[i];
int condition34 = (original == 34);
int condition35 = (original == 35);
int condition3 = (original == 3);
if (condition34 || condition35 || condition3)
   board[i] = original | 16;

:

if ((board[i] == 34) || (board[i] == 35) || (board[i] == 3))
   board[i] |= 16;

. , . 34, 35 3, 16 , .

, - , , , , .

, , , : , . - .

Answer 2

// , 32 0, [i]
board[i] = (randNum & 1024) ? 32 : 0;

AND

   xxxxxxxxxxx
 & 10000000000
 --------------
   ?0000000000 

? 1, 1 1024 0 . , 1, anser 32, 0. if else ? .

// , , 'X' '' putchar(board[i] ? 'X':' ');

?. [i] true, X else ' '