C++ :: How To Manipulate Bits Of All Types For Storing
Aug 10, 2013
I need a translate (in both directions) all primitive types, into char[] (will be stored in string)
I understand how to manipulate integral types with bits and I cant just cut them down and shift them, but float and double don't work with this manipulation. So, how I can create a perfect bit copy of float and double?
int i = 0xFCED03A4; //Random number
char c[4];
c[0] = ((i >> 3) & 0xFF);
c[1] = ((i >> 2) & 0xFF);
c[2] = ((i >> 1) & 0xFF);
c[1] = (i & 0xFF);
[Code]...
This is basic stuff but I need an equivalent for float and double types, and it needs to be a perfect BIT copy, not value copy.
So I'm supposed to write a code that asks a user for a string and then displays the hex, decimal, and binary code for each individual letter and then tells the user how many bits in binary were 1. For example: Enter a line of text: Hello
The ASCII code for 'H' is 0x48 in hex, 72 in decimal, or 01001000 in binary, 2 bits were set. The ASCII code for 'e' is 0x65 in hex, 101 in decimal, or 01100101 in binary, 4 bits were set. The ASCII code for 'l' is 0x6c in hex, 108 in decimal, or 01101100 in binary, 4 bits were set. The ASCII code for 'l' is 0x6c in hex, 108 in decimal, or 01101100 in binary, 4 bits were set. The ASCII code for 'o' is 0x6f in hex, 111 in decimal, or 01101111 in binary, 6 bits were set.
So far I've got a code that will display the binary bit pattern by shifting a mask and testing for a 1 or 0. The problem is I can't figure out how to make it so the 1's and 0's get put into a single integer rather than just printing out. I hope that makes sense. Here's my whole code.
Code:
#include<stdio.h> main () { int i; char input; printf ("Enter ........: "); scanf ("%c", &input); for (i = 1; i <= 8; i++)
I am trying to create a generic map container which shell contain data of different datatypes. I already found a solution in this forum here:
[URL]...
Introducing a container with a Base Class as content type and inserting objectes of Derived Class types from that Base Class suites my implementation very well. But it is not really working. I implemented it this way:
class MyType { public: MyType() {} virtual ~MyType() {} }; template <class PT> class ParseType : public MyType
[Code]...
Then I insert one element.
// index being an object of type Parser<string> ParseType<string>* test = new ParseType<string>( index ); // and index.val(0) = "-n" iMap.insert( pair< string, MyType* >( index.id(0), test ) );
Now I think I should be able to call
const string key("-n"); iMap.at(key)->content->val(n); Or iMap.at(key)->get_val(n);
But neither one compiles with the error that "class MyType" (as the map container is pointing to a MyClass object) has no member/member function "content"/"get_val".
I also tried introducing member and member function "content" and "get_val" in "class MyType", which I thought should be hidden while constructing ParseType<string>. This would compile but it does not call the member "content or member function "get_val" from class ParseType.
A second try was to remove templatization of "class ParseType" and introduce a specific, let's say, "class ParseString" for objects of type Parser<string>. But the problems remain the same either the compiler complains due to missing member/member function or retreiving the map content will not call the derived class member/member function.
#include <iostream> #include<fstream> int decryption(int); int multiply(int,int[][2]); using namespace std; main(){ int n; ifstream inFile; inFile.open ("out.txt");
[Code] .....
I was trying to store numbers read from a text file into 2D array but I am getting the error above.here is where the error occurs:
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?
int check_up(char string[]); int check_low(char string[]); void to_up(char string[]); void to_low(char string[]);
[Code] .....
When I compile this I have the following problems: warning: data definition has no type or storage class [enabled by default] in 'to_up(word)'conflicting types in 'to_up' function and to_low function warning: data definition has no type or storage class [enabled by default] into_up function error: unknown type name "word" in line 'printf("All uppercase %s. ", word):;'warning: parameter names (without types) in function declaration [enabled by default] in 'to_up(word)'and 'to_low(word)' 'note: previous declaration of "to_up" was here in function declaration of to_up function
My assignment is to write a binary calculator that works with floating point for simple math (+,-,x,/). How to do this. the binary numbers need to be from the user.
I've come to a point where I want to manipulate an image file at run time or with pre-determine sizes and have to be applied when the windows is moved or through in program options.
I know I can do the applying part. However I am a little unsure of how to tackle the image manipulation. I want to make it so that it is not os dependant. So I know I can not rely on any os functions. The only other thought that came to mind was to deal with the video card itself.
So the main question after all of that is said and done. How is c++ able to interact with the video card directly for images? Or if there are existing function I can use. How do they do that? If I can use existing function I would like to be able to manipulate it myself.
How I can manipulate certain strings. This program here is supposed to randomly scramble any word/sentence input. However, I notice that even the empty spaces get moved; is there any way to stop that from happening? I would want the empty spaces to stay in their input positions.
here i have an assignment, creating a longInt class and using it to calculate large numbers, i dont have a clue how to manipulate a whole array as a single ineteger.
I'm trying to write a program that manipulates a doubly linked list. My professor wants it to have two structs, one called Node (containing the data, and pointers to the next and previous nodes) and one called DLList, which contains the nodes for the head and tail (which is then passed to all of my functions).
I'm a little confused how to access the head and tail, for instance, if I want to initially set them to null in the main function (he emphasized the need for this), or to use them in my functions. I've tried a lot of variations to call the head and tail, but I keep getting told that head and tail are undeclared in the function.
How might I access my head and tail, for instance in a main function, when they're defined like this? (I took out all of the logic in my functions for clarity)
Essentially what I need to do is take a text file, ("input.txt"):
4 4 1 0 0 1 1 1 1 1 0 0 1 0 0 0 1 0
And take the first two values on line 1 (4, 4) and use them as length and width. Number of rows: 4 Number of columns: 4
Then I need to print out the matrix and further manipulate it. I need to find the sum of the 1's per column and then take that number and replace each 1 with the 1's in each column.
The part that's mostly troubling me is that my instructor will be giving me the input file with random values, so I don't know what the matrix dimensions will be.
I can read the 2D array but can't seem to use it after. I need to find a way to skip the first line, and then read in the matrix and be able to use it mathematically to add up each column.
I made a program that can use a function to manipulate data from a list class. The program is very basic and I think the error makers may be obvious to some of you. I just wanted to find it without having to scrap my program. It doesn't generate a compile error but it announces a memory error while it is running. I use visual studio 2012, the program is an exercise from a c++ book.
list.h #ifndef LIST_H_ #define LIST_H_ typedef double Item; const int MAX = 10; class List
Create an application to manipulate an array of student record objects. A student record will consist of a name (first, middle, and last), an ID number (9 numeric digits, cannot be more or less), an address (street, city, state, and 5 digit Zip code), and a phone number (3 digit area code and 7 digit number). The application will support an array of students. The user will be allowed to enter records from the keyboard, sort records by either name (last, first, middle) or by ID, save the records to a disk file (name supplied by user), and read the records from a disk file (name again supplied by user).
Create a fixed length string that must check that the length of the string is the required length. The fixed length class should be done as a template with the number of characters as the template argument. From this fixed length string, derive a class to hold digits of a fixed length.
Create component classes as necessary to use together to implement the student record class.
Use either the array template created in an earlier lab to handle the array or you may use the vector class from the STL to handle the array of student record objects.
The maximum number of students will be 25 (it may be less).
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.
Using 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?
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 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.
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++) {
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
