I have a double variable and depending on certain conditions I need to set certain bits of an unsigned short Variable. For example, if double var is odd I need to set the 15th bit of the unsigned short variable.
View 4 RepliesHow can i write a function that will read an "unsigned integer" into a variable of type "unsigned short int"? i can not use cin >> inside the function.. so i am looking for atleast a hint!
View 16 Replies View RelatedI've stored a binary pattern in what is interpreted as an unsigned short.
unsigned short byte_one = 128;
I've done some bitwise manipulation and want to store it back into an array, however, it needs to be null-terminated.
buf[1] = byte_one;
How do I null-terminate this?
i want to ask how many bits are created when write this line
unsigned exponent:10;
is exponent locate a 10 byte from memory or 10 bits ?
I need to convert the bit representation of an unsigned char into a string.
so like 254 would be "11111111"
I'm having some trouble where no matter what number I try to convert I get 01111111.
string bin2string(unsigned char N) {
string sN(8,'0');
unsigned char X;
unsigned char Y = 0;
for(int i = 0; i < 8; i++){
[Code] ....
I am working on a project where I need to retrive a double number and store 8 bits of the number in one field and the other 16 bits in another field. the code below gives me an error.
lata= lat>>8;
latb = (lat & 0xff);
The error states that & and >> are illegal for double. With this in mind, can I use these on a double. If not what can I do to achieve what I am trying to do?
size of int is 2 bytes and of short int is also 2 bytes.The range of values for int and short int are the same.
Then why int and short int are used? only int or short int is enough ....
i am using the below logic. but it gives me error when i am setting the bit_position 15 or 16. i suspect, the problem with the integer range.
short bit_map, bit_position
bit_map = bit_map | ( 1 << bit_position )
I'm trying to return a short int in a function..This is my function signature :
short int* StartRecord(int seconds)
this is my array :
short int waveIn[NUMPTS];
I'm trying to get the data into an array :
short int arr [] = StartRecord(3);
getting this error: Error2error C2440: 'initializing' : cannot convert from 'short *' to 'short []'
I am using print/sprintf with a "%i" format string. Works fine if the input is indeed a 32bit integer. But how can i put in 8/16 bit (ie short & byte) 'integers'? If i just throw them in, they are always taken as unsigned, as the topmost bit/s is/are casted to zero... [URL] ....
View 3 Replies View RelatedI'm having trouble reading a block of bytes into a vector of short ints. My code is as follows:
Code:
FileStream.seekg(2821);
vector<short> g_Data;
int iter = 0;
g_Data.reserve(maxNumOfInts);
[Code] ....
The relevant block of data starts at offset 2821 in the file. Every two bytes are a signed short integer. What's odd is that it's giving me the correct results only part of the time. At offset 1052421 and 1052422 there are two bytes 40 and 1F that are correctly read in as 8000, but at offset 1052415 and 1052416 bytes 88 and 13 are read in as -120 instead of 5000.
I don't see anything wrong with my code, though, unless I'm misunderstanding completely how to convert an array of two bytes into a single float. Is my method correct? Better still, is there some way to just convert en mass an array of bytes into a vector of signed short ints?
Any function of simply converting character array to a short int?For example. char array[4]={'0','2','f','f'}; to short int 767?
View 3 Replies View RelatedI've been working on this project which inserts data for different types of books lately, and I'm trying to utilize inheritance and polymorphism. The issue I've been having is after I create an object with my MediaFactory, I go to insert data into that type of object, but it won't reach the correct child class. The parent class in this case is MediaData. The class I'm trying to reach is Childrens, and the class that falls in between is called Book. The function I'm calling to insert the information is setData(ifstream&). This function simply places the information from a txt file into an object with the insertion operator.
Right now the program runs into the setData function of Book instead of Childrens. I need Childrens so I can enter all the required attributes (title,author,year). The call to this function is in MediaManager through the function called buildMedia, and my test is running into the case if (type == 'Y'). From there a pointer of type MediaData is created and pointed to a new object returned of type Childrens. I'm using my debugger in Xcode which does show that the correct object type (Childrens) was created.
I've tried a couple things so far. First I created another function called getData. From there I passed in *media and infile (txt input file) into that function, which then passed it right into setData with a pointer to the object and infile in the parameter. That didn't work, so I also tried going back into Childrens and removing MediaData from all my virtual functions and replacing it with Book. I got the same result when that happened; It morphed into Book class instead.
I have a portion of my UML as a reference. Childrens is a Book; Book is a MediaData. I also included all code for MediaManager, MediaHash, MediaFactory, MediaData, Book, and Childrens.
I did not include the operator overloads in the .cpp files to eliminate some redundancy.
//-----------------------------------------------------------------------------
// MediaManager.h
// Manager class for MediaData type objects
//-----------------------------------------------------------------------------
#ifndef MediaManager_H
#define MediaManager_H
#include "MediaHash.h"
#include "MediaFactory.h"
#include "MediaData.h"
using namespace std;
class MediaManager {
[Code] ....
unsigned char key[32];
139 unsigned char rfseed[32];
173 f = fopen("/dev/urandom","rb");
174 fread(key,1,32,f);
175 fread(rfseed,1,32,f);
I am having problems copying outputs of the above code into other unsigned char other[32]. I need to keep the output of dev/urandom for backup. But, when I try to assign the values by memcpy(other, key, 32), the values do not match. The same problem happens by assigning values index by index in a loop.
I have done some experimentation on rvalue references with the TDM-GCC 4.6.1 compiler and made some interesting observations that I cannot explain away with theories. I have a very simple program that does not deal with objects but int primitives and that has defined 2 functions:
foo1 (returning a local variable by rvalue reference) and
foo2 (returning a local variable by value)
#include <iostream>
using namespace std;
int &&foo1();
int foo2();
int main() {
int&& variable1 = foo1();
[Code] .....
It seems the value returned by foo1 and received by variable1 dies out after some time - perhaps, a brief period of some milliseconds. Notice that I have prevented cout from printing "My name is softwarelover" by commenting it out. If I allow that statement to run, the result is different. Instead of printing 5, 0 it prints 0, 0. Seems like it is because of the time-delay introduced by "cout << "My name is softwarelover." that 5 turns into 0.
Is the above how an rvalue reference is supposed to behave when referring to a primitive integer which a function returned by reference as opposed to return-by-value? By the way, why is it 0, why not garbage?
Notice also that variable2 never seems to die out, no matter how many times I print it with cout! variable2 refers to a primitive integer which a function returned by value, not return-by-reference.
I am having a problem assigning bits a value of 0. The data is a 16 bit integer the bits greater than the 12th bit have garbage either a 0 or a 1. I would like to assign all bits greater than 12th bit the value 0 no matter what their values are. Whats the best approach.
View 5 Replies View RelatedUsing the old fashioned (unsigned) multiplication instruction in x64 assembly multiplies RAX (64 bit register) by a 64 bit register. The answer is stored in RDX:RAX (i.e. the answer is 128 bits). Is there any way, using native c++ to get the value in RDX (higher 64 bits)? One I can think of is: right/(limit/left) e.g. if we are limited to a byte then 97*123 would overflow:
97/(255/123) = 46 times, which is RDX's (if it was one byte) value. But this is too inefficient. Is there a fast way?
Value x is a 32-bit unsigned integer 3:
00000000000000000000000000000011
If we use bitwise-shift to shift all bits to the right by 2, x is 0:
00000000000000000000000000000000
If we then do a bitwise leftshift on x by 30, do we end up with:
11000000000000000000000000000000
or
00000000000000000000000000000000
In other words, when we perform right shift which clips away the least most significant bits, and then do a left shift, is it possible for those bits to reappear?
I am trying to retrieve the first three bits of a number. The code that I am using should work but it isn't giving me the correct result when trying certain numbers. Below is the code I am using:
unsigned short num1, num2 = 0;
unsigned short num = 65535// binary 111111111111111
num1 = num && 0x07;// gives me 1 but should give 7(111)
num2 = num >>3;//gives me 8191, which is correct
Why I am not getting the first three correct bits(111)?
I am working on a project where I need to reverse bits for a number.
For example, if I have 110111100000000 I need to reverse it to 0000000001111011.
I'm trying to write a program that writes data to a disk in C++ without caring about it's file system. Here is what I can do so far:
#include <iostream>
#include <unistd.h>
#include <fcntl.h>
using namespace std;
char buffer[] = "Wow! I'm writing this data to a disk without puttting it into a file!";
int main(){
int Disk=open("/dev/sdb",O_RDWR);
write(Disk,buffer,sizeof(buffer));
close(Disk);
return 0;}
But this program can only write ASCII characters to the disk. But what if I want to mainipulate bits on the disk, how would I do that?
I am trying to encrypt a plaintext using DES in C. I read about the algorithm and how it works, but when i came to write the code i struggled. :
How to locate the lowest 8-bits in a 64-bit key ?
How to shuffle the plaintext according to the algorithm description ? (I read about bitwise operations, but i still cannot understand how i can use them to transfer for example the 5th bit to the location of the 30th bit)
Left shifting the key would not wrap the bits, so i just bitwise or with a mask that will add the bits that did not wrap around?
I'm working on an assignment where I have to read an image in the PPM format. This format consists of a header that contains the parameters and the rest is raw bits.
I have to work with a modified PPM image that contains a secret message. This message is stored in the first X number of bytes. To decode a single character I would have to look at the lowest level bit of 8 bytes and return that as a character, then repeat this for the length of the message.
The code below is what I have so far, but I do not get the expected output but instead I get smiley-faces.... or other ASCII characters depending on the shift.
char buffer = 0;
int MsgSize =(size*8);
int nRead = 0;
printf("The secret message is displayed below: ");
for(i; i<MsgSize; i++) {
[Code] ....
I just have a short question! I have an sbyte and I want to convert it to an int, but I do not want a value conversion, just to copy the bits, such that the negative numbers in the sbyte will be their complement in the int (-12 in sbyte -> 244 in int)... How can I do that?las
View 1 Replies View RelatedI have a 64-bit uint64_t number:
Code:
Primitive<uint64_t> b = 0xCCCCCCCC00000000; I need to save the first 31 (most important) bits - 7FFFFFFE.
I found this solution in the Internet:
Code:
start = (((b)>>(first)) & ((1<<(((last+1)-(first))))-1)); but in my case for this code:
Code: Primitive<uint64_t> start = (((b)>>(32)) & ((1<<(((63+1)-(32))))-1));
I get an error: left shift count >= width of type
And even if I change 63 to 62:
Code:
Primitive<uint64_t> start = (((b)>>(32)) & ((1<<(((62+1)-(32))))-1));
I get: error: integer overflow in expression
I was trying to program an decimal to binary converter (8-bits) in C. I am a complete beginner so I tried to put the 1's and 0's of the binary number as they come without reversing the order for beginning. I have seen example on the internet but didn't understand them so I decided to write it as I understood it. So, I typed the code as shown below:
Code:
#include <stdio.h>
#include <stdlib.h>
int main() {
int number;
int BitNum[8], x;
[Code] ....
The problem with the code is that if binary form has 0s in it then program displays a random number instead of a 0. For example if decimal is 7, it should print out 11100000 but it displays only 111(and some stupid numbers instead of 0). I have tried to solve it but failed.