Thread: Binary Output

Hi there, i currently have strings with hex values in,

is there a way i can print to see the binary value (im playing around trying to shift bits left and right)

such as

%x prints hex
%c char etc is there one for binary or what is the easiest way to do it?

Far as I know there's no %binary function in printf()... but it's pretty easy to fake with about 5 or 6 lines of code.

You know the underlying storage of integers in all number bases is binary, so you're already half way there.
What you need to do is stop and think about the problem... how can you look at only 1 bit of a binary number?

Honest it's not hard...

If you get stuck, post your code and we'll see what we can accomplish.

Originally Posted by r_james14

Hi there, i currently have strings with hex values in,

is there a way i can print to see the binary value (im playing around trying to shift bits left and right)

such as

%x prints hex
%c char etc is there one for binary or what is the easiest way to do it?

To print a value in binary you could use itoa and specify the base. You could also create your own function, if you want to obtain the result as a long long or a long.

You may find this tutorial useful:
Dystopian Code: Radix Conversion in C

This is related to what I'm trying to achieve but don't really fit under the thread header.

I am currently writing code for CanOpen which uses 8 predefined bytes. Each byte has a different role. It also use little endian.

If i put hex value 3 into a byte (2 bits, 11) is there a way i can make sure the code recognises the fact that the value should be 00000011. Or as it is little endian should it be 11000000 in which case i can just shift bits to achieve it?
thanks

okay so since my last annoying questions ive done alot more reading and since realised that endian big/little refers to byte order and not bit order.

So if i have a hex value ABCD which i need to split over two bytes.

SendData [2];
SendData [3];

What is the best way to break the string up so SendData[2] = CD and SendData[3] =AB.

Im not asking for anyone to do it for me, just is the already a feature to do this is a really simple way that i can't think of atm.

Thanks

James

Im sure im going to annoy everyone today with amount of posts.

Ive taken the suggests from previous post and had a go at implementing it. Code is below.

Problem is if i assign n.x = 0xABCD; in the union in my function the output is perfect. However is i change it to n.x = Index then it only picks up the CD not the AB. My code is put below.

Code:

#include <stdio.h>


char SendData[8];
static void MakingSDOmessage(char Index, char SubIndex, int Value);
int i;


main()
{


MakingSDOmessage(0xABCD, 0xe3, 0);


for ( i=0; i < 8; i++)
  printf("SendData[%d] = 0x%x\n", i, SendData[i]);






while(1)
{
}
}


static void MakingSDOmessage(char Index, char SubIndex, int Value)
{
union number {
    short int x;
    char bytes[2];
};
    
    union number n;
    n.x = 0xABCD;
    SendData[1] = n.bytes[0];
    SendData[2] = n.bytes[1];
    SendData[3] = SubIndex;


}

solved it, it was because i had to use wchar_t to define the char Index

should the following code work?

i keep getting a n: hasnt been initialized warning and some strange results for the SendData[4] -- [6]

Code:

#include <stdio.h>


#define Output 0xABCD
 
char SendData[8];
static void MakingSDOmessage(wchar_t Index, char SubIndex, wchar_t Value);
int i;
 
 
main()
{


MakingSDOmessage(Output, 0xa9, 0x17A120);
 
for ( i=0; i < 8; i++)
  printf("SendData[%d] = 0x%x\n", i, SendData[i]);
  
while(1)
{
}
}
 
static void MakingSDOmessage(wchar_t Index, char SubIndex, wchar_t Value)
{
	union index {
		short int x;
		char bytes[3];
};


    union index n;
    
	n.x = Index;
	SendData[0] = 0Xe2;
    SendData[1] = n.bytes[0];
    SendData[2] = n.bytes[1];
    SendData[3] = SubIndex;


    n.x = Value;
	SendData[4] = n.bytes[0];
    SendData[5] = n.bytes[1];
	SendData[6] = n.bytes[2];
}

hi there, i tried the uint16_t and it just will not compile on visual studio 2008 also my "value" entry is 32 bit. As regards putting the data into an array or structure i'll still have the fundamental issues i have of splitting up the values up.