Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

C++ binary and decimal conversion

Posted on 2013-06-23
7
Medium Priority
?
453 Views
Last Modified: 2013-06-24
I am looking for a good way for the following conversion in C++:

41283 is binary digit “1010000101000011”
From first bit,
Structure ID:101¿5 (decimal)
Item No.:0000101¿5 (decimal)
Route No:000011¿3 (decimal)

Thank you.
0
Comment
Question by:cytello
7 Comments
 

Author Comment

by:cytello
ID: 39269979
Sorry about the strange characters

1. I need to convert 41283 to binary as 1010000101000011
2. convert the first 3 bits 101 to decimal
3. convert the next 7 bits 0000101 to decimal
4. convert the next 6 bits 000011 to decimal

Is there a way to get the decimal values for the 3 bits, 7 bits, and 6 bits?
0
 
LVL 86

Expert Comment

by:jkr
ID: 39270179
If you only want to read that data (and not write it), a simple bit shifting/masking approach will do - otherwise I'd point you to 'bitsets' (http://www.cplusplus.com/reference/bitset/bitset/) or 'bitfields' (http://en.wikipedia.org/wiki/Bit_field). But, in your case, that can be done like

short int val = 41283; // 16 bits

short int structID = (val & 0x1c00) >> 13;
short int itemNo = (val & 0x01fc0) >> 6;
short int routeNo = val & 0x003f;

Open in new window

0
 
LVL 8

Expert Comment

by:lomo74
ID: 39270533
the opposite procedure would be:
unsigned short int val1, val2, val3, num;
val1 = 5;
val2 = 5;
val3 = 3;
num = (val1 & 0x07) << 13 |
	(val2 & 0x7F) << 6 |
	(val3 & 0x3F);

Open in new window

0
Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 14

Accepted Solution

by:
frankhelk earned 2000 total points
ID: 39270740
And here the elegant (bitfields) way to let the compiler sort the stuff out:
#include <stdio.h>

typedef union 
{
	short value;
	struct
	{   // stacked backwards !
		unsigned int RouteNo:6;
		unsigned int itemNo:7;
		unsigned int structId:3;
	} fields;
} bitfield;


int main()
{
	bitfield val;

	val.value = 41283;

	printf("StructID : %d\n", val.fields.structId);
	printf("ItemNo   : %d\n", val.fields.itemNo);
	printf("RouteNo  : %d\n", val.fields.RouteNo);

	return 0;
}

Open in new window

Easier to understand, and more simple to use thruout the code. And more easy to handle if the coding of the bitfield changes.

Output would be
StructID : 5
ItemNo   : 5
RouteNo  : 3

Open in new window

0
 
LVL 8

Expert Comment

by:lomo74
ID: 39270770
0
 
LVL 35

Expert Comment

by:sarabande
ID: 39271832
cytello, is it homework?

if yes, you may post the complete assignment such that we could help you to writing your own code.

generally, converting a string number from one base to another (in your sample it is from base 2 to base 10), you easily could do it by extracting each digit from right to left, convert the digit to number, multiply it with the base^n  (where n is a loop counter beginning at 0) and add the result to the total.

for '110' you would get 0*2^0 + 1*2^1 + 1*2^2 = 0 + 2 + 4 = 6.

Sara
0
 

Author Closing Comment

by:cytello
ID: 39271927
Thank you.
0

Featured Post

Concerto Cloud for Software Providers & ISVs

Can Concerto Cloud Services help you focus on evolving your application offerings, while delivering the best cloud experience to your customers? From DevOps to revenue models and customer support, the answer is yes!

Learn how Concerto can help you.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article will show you some of the more useful Standard Template Library (STL) algorithms through the use of working examples.  You will learn about how these algorithms fit into the STL architecture, how they work with STL containers, and why t…
Basic understanding on "OO- Object Orientation" is needed for designing a logical solution to solve a problem. Basic OOAD is a prerequisite for a coder to ensure that they follow the basic design of OO. This would help developers to understand the b…
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be relat…
The viewer will learn additional member functions of the vector class. Specifically, the capacity and swap member functions will be introduced.

971 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question