I am currently working with win32 API , for image processing, one of the windows function returns RGBA ( colors ) as unsigned int , I then split it into individual bytes by creating a union ,
Code:
union colour {
unsigned int value;
unsigned char RGBA[4];
}
to spit the int into individual bytes, my Question is there a better or my convenient way of doing this.
creating a bitmap. Our professor wants us to creat a black 100*100 bitmap.
Code:
#include <stdio.h>
#include <stdlib.h>
#pragma pack(push,2)
typedef struct{
[Code].....
I dont even know where to start. I spend the last 7h infront of my computer and i'm so frustrated cause my professor gave us no information what so ever. At the moment its more of a trial and error process than anything else.
How would i set the color of an individual pixel for examplel or how would i save the file ?
Any way that one could create a bitfield using the standard technique of creating a structure within a union, as follows:
Code:
typedef union {
struct {
unsigned b0 : 1;
unsigned b1 : 1;
:
:
unsigned b(n-1) : 1;
} bits;
unsigned int value;
}
BIT_FIELD_TYPE; Except, what I'd like to do is to replace all the single-bit elements in the bits structure with a single statement that creates an array of, say, 32 values. The clear advantage of this is that it could be traversed using an iterator, ...
Code:
main() {
BIT_FIELD_TYPE foo;
unsigned int i;
...
for (i = 0; i < n; i++) {
... (print out foo.bits.b[i]) ...
}
So far, I've not figured out a way to do it, either as an array, or using a pointer to iterate through the individual bits.
In the program I'm writing, I'm creating a linked list of students with individual data read from a file. At the moment, I have written two functions to accomplish this; one that creates a student node and fills it from a line file, and a second that calls on the first to create a linked list. It seems to work fine except for one thing; It seems that EOF is being reached first, but the function continues on anyways? Here is my code so far...
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
struct student
// Declaring student structure globally.
[Code] .....
And here is what the input file would look like...
Thui Bhu, 100, 90, 80, 100, 89, 99, 88
Ariana B. Smith, 90, 90, 100, 100, 99, 100, 95
Emily Gonzales, 100, 90, 100, 70, 78, 78, 80
Jennifer L, 80, 90, 90, 100, 89, 99, 85
Maria Jones, 65, 72, 77, 68, 62, 70, 65
Bill Gates, 60, 54, 38, 62, 65, 60, 50
Escobar Morris, 83, 77, 88, 76, 79, 72, 76
Anne Latner, 80, 80, 85, 95, 90, 95, 98
John Doe, 45, 87, 88, 89, 67, 96, 79
And here is what the output is...
EOF
EOF in create_record
Thui Bhu: 100 90 80 100 89 99 88
Ariana B. Smith: 90 90 100 100 99 100 95
Emily Gonzales: 100 90 100 70 78 78 80
Jennifer L: 80 90 90 100 89 99 85
Maria Jones: 65 72 77 68 62 70 65
Bill Gates: 60 54 38 62 65 60 50
Escobar Morris: 83 77 88 76 79 72 76
Anne Latner: 80 80 85 95 90 95 98
John Doe: 45 87 88 89 67 96 79
Press any key to continue . . .
I am new to C programming, I have been given an assignment to create a simple calculator by splitting the program in 3 files. It should have 2 .c files and 1 .h... I went through the internet extensively and could only come up with this.
main.c:
Code:
//Calculator main.c
#include <stdio.h>
#include <conio.h>
#include "Functions.h"
int main() {
float x = 0, y = 0;
int operation;
[Code]...
Functions.c
Code:
#include "Functions.h"
extern float x, y;
float addition (float a, float b) {
return a + b;
[Code]...
Functions.h
Code:
#ifndef FUNCTIONS_H_INCLUDED
#define FUNCTIONS_H_INCLUDED
float Sum(float a, float b);
float difference (float a, float b);
float remainder (float a, float b);
float product (float a, float b);
#endif
When I do a 'cl main.c' on the Developer Command window for VS2013, i get an error that reads :
main.obj
main.obj : error LNK2019: unresolved external symbol _difference referenced in function _main
main.obj : error LNK2019: unresolved external symbol _product referenced in function _main
main.obj : error LNK2019: unresolved external symbol _addition referenced in function _main
main.exe : fatal error LNK1120: 3 unresolved externals
how to accommodate double-size:8 bytes in 4 bytes pointer in 32bit system.
View 1 Replies View RelatedCode:
int i12 = 1001;
cout << i12 << " " << &i12 << endl;
gives the result: 0x7fff0d065098
It's 6 bytes, but I'd expect the address to be 8 bytes on my 64 bit machine. I am using Ubuntu 12.04, GNU compiler.
So, why the address is 6 bytes and not 8 bytes?
I'm trying to use a structure in union in the following format:
Code:
union data
{
unsigned char All[10] ;
struct data_pkt
{
unsigned char ack;
unsigned short status;
unsigned short data_length;
unsigned char Data[5];
}format;
}adb; adb.
All has 10 bytes which is equivalent to the structure bytes. ie 6 bytes if unsigned char and 2 short i.e 4 bytes. Thus total 10 bytes is given to adb.All. When I print the struct size I get 12 bytes. This creates problem in obtaining data in union. According to the program:
adb.format.ack should have the address of adb.All[0]
adb.format.status should have the address of adb.All[1]
adb.format.data_length should have the address of adb.All[3]
adb.format.Data[0] should have the address of adb.All[5]
But in actual case this is how memory is allocated:
adb.format.ack assigned to the address of adb.All[0]
adb.format.status assigned to the address of adb.All[2]
adb.format.data_length assigned to the address of adb.All[4]
adb.format.Data[0] assigned to the address of adb.All[6]
Why this is happening? How can I solve this?
How I could use unions to combine registers elegantly. For example I have the 8 bit registers B and C & I have opcodes that work on each independent register such as add b, c, which is simple, but then I also have opcodes that work on both of them as if they're one like ld a, bc. I know I could go about that by just masking them together but I've seen it done with unions before & it made everything so much more simple.
View 4 Replies View RelatedIn the current code,We are using pointer of union and assigning value.
class sample {
union {
short *two_int;
int *four_int;
double *eight_real;
char *one_ascii;
// void *v;
}; }
Than we assign value in following way.
sample.four_int[0] = (x + xoff); ( x and xoff and y and yoff all are integer)
sample.four_int[1] = (y + yoff);
Than we write data into file. it was working fine into 32 bit machine but it is not working 64bit machine. When I compare data and found that data is divided by 4. For Ex The File generating from 32 bit machine contain 80 than 64 bit . File contain 20.
I have made VGA emulation with registers and memory in my emulator. But for some reason the writes to the union array with CPU data (register 0-8 of the VGA's Graphics Controller Registers, referenced with <GRAPHREGS>.DATA[index]) don't reflect on the union's data.
typedef union __attribute__((packed)) {
byte DATA[9]; //9 registers present!
struct //Contains the registers itself! {
//Set/Reset Register (index 00h)
union {
[code]...
what's going wrong? Have I made an error in the registers?
(In this case I write to register <GRAPHREGS>.DATA[8] (which should be the <GRAPHREGS>.REGISTERS.BITMASKREGISTER)), but the BITMASKREGISTER stays 0, while DATA[8] gets the correct value.
I have the following C++ code
typedef union UUID {
unsigned char byte[16]; /**< Array of 16 bytes. */
unsigned int ll[2]; /**< Array of two 64-bit words. */
} UUID;
[Code] ......
The compiler complains thus
$ g++ union.cpp
union.cpp: In function "int main()":
union.cpp:15:17: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x
union.cpp:15:17: warning: extended initializer lists only available with -std=c++0x or -std=gnu++0x
union.cpp:15:17: error: no match for "operator=" in "entry.EntryHeader::uuid = {0, 0, 0, 2}"
union.cpp:1:20: note: candidate is: UUID& UUID:perator=(const UUID&)
How do I go about assigning values to this union in C++.
I haven't actually learned how to use arrays yet but I know the basic principle of it and decided to try and implement one to improve my code. I'm sure the thing is a bug ridden mess but I would particularly like to point your attention to the function sortDenomination(). Is what I am trying to do in the loop possible?
The reason why I want to do it this way and not with if statements for each denomination is because I can then easily apply this to the second part of the assignment which sees us split a double into dollars and cents and then process each separately. All I would have to differ for each is change the money_loop variable to include the last two denominations in the array.
Code:
#include <stdio.h>
/*Reads cents input from the user.*/
void getCents(int &read_cents) {
printf("Please enter the amount of cents between 5-95:
[Code] .....
I'm supposed to write a code that takes an integer and splits it into individual numbers e.g. 234 becomes 2 3 4 .the individual numbers are then passed on to a function that accepts only one number at a time
All i could think of was this,but its a very bad method coz i dont know how long a number would be inputed into "Angle_in_degree"
Code:
int Angle_in_degree,a,b,c
c= Angle_in_degree %10;
b=Angle_in_degree/10 %10;
a=Angle_in_degree/100 % 10;
function(a);
function(b);
function(c);
I'm trying to get this program to work that will count the frequency of each vowel.
#include <iostream>
#include <string>
using namespace std;
int main(){
char sent[81];
cout << "Type up to an 80 character sentence." << endl;
cin.getline(sent, 81);
[Code] .....
Classes defined with struct and union
Classes can be defined not only with keyword class, but also with keywords struct and union.
The concepts of class and data structure are so similar that both keywords (struct and class) can be used in C++ to declare classes (i.e. structs can also have function members in C++, not only data members). The only difference between both is that members of classes declared with the keyword struct have public access by default, while members of classes declared with the keyword class have private access. For all other purposes both keywords are equivalent.
The concept of unions is different from that of classes declared with struct and class, since unions only store one data member at a time, but nevertheless they are also classes and can thus also hold function members. The default access in union classes is public.
The above is a statement taken from a C++ tutorial. So I understand classes a bit better now but the above quote doesnt make too much sense. Is it saying that you can have a class within a class?
What i'm interested in is the behavour of a struct/union constructed like this:
Code:
typedef struct {
uint64_t num1;
uint64_t num2;
} st_a;
typedef struct {
uint64_t num1;
uint32_t num2;
[Code] .....
What kind of behavour could I expect from object, in the following cases:
1. newsomestruct(0)->u.a.num1 = 2;
2. newsomestruct(1)->u.b.num1 = 2;
3. newsomestruct(0)->u.a.num2 = 2;
4. newsomestruct(1)->u.b.num2 = 2;
5. newsomestruct(0)->u.b.num1 = 2;
6. newsomestruct(1)->u.a.num1 = 2;
7. newsomestruct(0)->u.b.num2 = 2;
8. newsomestruct(1)->u.a.num2 = 2;
9. Code:
somestruct* ss1 = newsomestruct(0);
somestruct* ss2 = newsomestruct(1);
* ss1 = * ss2; 10. Code: somestruct* ss1 = newsomestruct(0);
somestruct* ss2 = newsomestruct(1);
* ss2 = * ss1;
This is what I'd expect, but I can't find any evidence online in C standards or elsewhere:
1. Works as expected, sets the value of a.num1 to 2.
2. Works as expected, sets the value of b.num1 to 2.
3. Works as expected, sets the value of a.num2 to 2.
4. Works as expected, sets the value of b.num2 to 2.
5. Works as expected, sets the value of b.num1 to 2.
6. Works as expected, sets the value of a.num1 to 2.
7. Works as expected, sets the value of b.num1 to 2.
8. Crashes/Memory Corruption, attempted to alter memory outside struct.
9. Works as expected, * ss1 == * ss2
10. Crashes/Memory Corruption, attempted to alter memory outside struct.
I've tested simular code on my machine (Xubuntu 14.04LTS compiled with gcc on -O3) and it appears to be reliable, given that you stick with acessing the type tagged in the struct or the common initial union struct members (in this case num1).
I have union of pointer.
union {
short *two_int;
int *four_int;
double *eight_real;
char *one_ascii;
// void *v;
};
We have write function which write into file.
fwrite (r.one_ascii, 1, i, outstr);
I found one thing,When we write function, we fill only four int in following way.
r.four_int[0] = x + xoff;
r.four_int[1] = y + yoff;
So my question,we fill four_int but write one_ascii only.As is it union of pointer. So it does not matter. I am using 64bit machine and do not have any issue in 32 bit machine.
For more information: [URL] ....
how to find out which member of union is currently set/active.
exm:
union myunion{
int i;
float f;
}
if i set myunion ob{7}, it set ob.i=7;
my q? is how to find out i is set f is not set/ not acrive
It involves some discrete mathematics. Any code snippet to get me started?
View 3 Replies View RelatedI'm a C beginner. I have questions, let say if I have a structure of message containing of Id, Length, and 3 bytes of data, and I want to manually saved in individual bits of data, how can I do that? I confused on how to use typedef struct and union. Below is the sample code:
typedef struct {
uint8_t Id;
uint8_t Length;
uint8_t DataField[3];
}AA;
[Code] .....
By the way, the DataField is declared as above. It's not necessary for a data to be 24 bits. It can be bit 0 - bit 8, it can be bit 10 - bit 15 and so on. So, for each case, I want to ignore the other bits.
I'm trying to right the function that puts the correct letters in the right positons being reported from my previous compareletter function for my game of hang man and its not updating the word in progress array. Here's my compare letter function that's working correctly:
Code: //function that returns the index of the letter that the user has guessed or Code: //-1 if the letter isn't in the word
int CompareLetter(char array[], char guess, int numLetters)
{
int i;
[Code....
However, this isn't changing any of the position of the asterisks in the word in progress array positions 0-3.
Basically I am making a console RPG (isn't every beginner nowadays?) and I am having an incredible amount of trouble assigning specific characters their own color. e.g. monsters being red, cash being green, etc.
I took out Left, Right, and Down controls because of character constraint.
#include <iostream>
#include <windows.h>
//%%%%%%%%%%%%%% COLOR CALL %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
void setcolor(unsigned short color) {
HANDLE hcon = GetStdHandle(STD_OUTPUT_HANDLE);
SetConsoleTextAttribute(hcon,color);
[code]....
i am developing a multi-lingual application allowing users to change language as well as keyboard layouts (through combobox). I am able to change the culture of application successfully but i'm unable to change the individual keyboard layouts e.g. for English (United States), im unable to change layouts from QWERTY (default) to Dvorak - Left hand etc... I don't just want to change the input language, i was also want to be able to type in different keyboards. Here's the code (e.g. for English language), the imports etc are added already..
CultureInfo TypeOfLanguage = CultureInfo.CreateSpecificCulture("en-US");
System.Threading.Thread.CurrentThread.CurrentCulture = TypeOfLanguage;
InputLanguage l = InputLanguage.FromCulture(TypeOfLanguage);
InputLanguage.CurrentInputLanguage = l;
The program is to find intersection,union and difference of two sets. The program take the input correctly but after it crashes with the message that some exe is not working...
Code:
#include<iostream>
using namespace std;
void Input(int *A, int*B, int size1, int size2)
//input function {
[Code] ....
I'm trying to come up with the union of two Vector ADT bags, so I have to overload the '+' operator, but I'm getting a bunch of error messages saying:
VectorBag.cpp: In instantiation of ‘VectorBag<ItemType> VectorBag<ItemType>::operator+(VectorBag<ItemType>) [with ItemType = int]’:
proj2.cpp:161:42: required from here
VectorBag.cpp:81:24: error: no match for ‘operator[]’ (operand types are ‘VectorBag<int>’ and ‘int’)
newBag.add(anotherBag[i]);
^
Here is the function to overload the operator:
template<class ItemType>
VectorBag<ItemType>
VectorBag<ItemType>::operator+(VectorBag<ItemType> anotherBag) {
VectorBag<ItemType> newBag;
for (int i = 0; i < anotherBag.getCurrentSize(); i++)
newBag.add(anotherBag[i]);
}
The add() function is pre-defined by me somewhere else in the code. It basically does push_back().