C :: Encrypt Message Within BMP File - Incorrect Struct Size
Feb 9, 2015
I'd wrote a program to encrypt a message within a bmp file using my own structs and all for everything (yes, call me a ........head) The program works but for some weird ........ing reason I was forced to subtract 2 bytes from the header size to get the correct value. I've narrowed down the issue to my BmpFileHeader struct.
Here's a short program that demonstrates the issue:
Code:
#include <stdio.h>
#include <stdlib.h>
#define BYTE unsigned char
#define WORD unsigned short
#define DWORD unsigned long
#define LONG signed int
[Code] .....
Tried with both gcc and TinyCC and got the same result so it doesent seem to be a compiler bug. Microsoft's structures though are giving the correct size, even though they have the exact same definition.
Microsoft's defines:
Code:
// windef.h
typedef unsigned long DWORD;
typedef unsigned char BYTE;
typedef unsigned short WORD;
[Code] .....
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Sep 14, 2014
#include <stdio.h>
#define MAX_USERS 20
struct {
char ID[10];
char Name[40];
int Pos;
[Code] .....
I was attempting something weired with address to move data around when I discovered that the size of the array is not what I expected. I am passing this structure as &Users to a function that declares it as a void *, then I can deal with chunks of data (memmove) and not have to worry about index or things like that. However...sizeof is returning something I do not understand.
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Jul 11, 2013
I was wondering why, in C, the sizeof of a struct is larger than the the sum of all the sizeofs of it's members. It only seems to be by a few bytes, but as a bit of a perfectionist I fine this a bit annoying.
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Jul 15, 2014
I made my own custom message/dialog box.
I have a template mock up view using xaml. I have a viewmodel that raises the message property. I binded the message property to a textblock inside my xaml.
Since my messages are different for every viewmodel I have.
E.g.in every viewmodel, I have something like
messagewindow.Message = "This is a new message";
dialogService.ShowDialog(Success, messageWindow);
In one of my messages, I want to make the font bold and different color for a specific message segment.
How can I do that without messing up with the other messages that inherit from the xaml or code behind?
Currently, I'm not using any code behind and a lot of the examples online I've seen use code behind and/or don't have dynamic message textboxes.
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Mar 18, 2013
My program attempts to encrypt a file using XOR operator. However, when I attempt to encrypt a file, it says "Error in reading file", (a printf function I set up if the program could not read the file, obviously). The problem is that I don't know what's causing this. Instead of encrypting the file, it just deletes all the characters in it, so I put in a fprintf to put place some text into the file. Here is the code:
Code:
#include<stdio.h>
#include<string.h>
int encryptd(FILE *);
int main(void)
{
FILE *fileptr;
int recode;
char fname[25];
[Code]...
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Jan 1, 2014
I am writing a program in which the computer will read a txt file and encypt it. The encryption works fine, but the computer cannot read the file perfectly. If there's a newline, the scanning process stops. For example I have the following text in the txt file.
One two three four five
(newline) Six seven eight
The computer will stop reading after 'five'. I assume that is because I use fgets.
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Dec 14, 2014
I'm having trouble figuring out how to find the size of an array program that involves "struct."
#include <iostream>
using namespace std;
struct d{
char* a;
float b;
int c;
[code].....
When I run this program, the output is 80(for my compiler). That would mean that each element in the array is 16 bytes but I don't understand how struct d is 16 bytes.
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Apr 20, 2013
typedef struct Element Element;
struct Element {
char x;
double* y;
[Code] .....
This one with y pointer gives 8
typedef struct Element Element;
struct Element {
char x;
double y;
[Code] ....
This one with a normal y variable gives 12
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Mar 6, 2015
The WinAPI has a struct like this for raw input:
Code:
typedef struct tagRAWINPUT { RAWINPUTHEADER header;
union {
RAWMOUSE mouse;
RAWKEYBOARD keyboard;
RAWHID hid;
} data;
[code]...
The definition of the struct doesn't show it but the documentation says that bRawData is variable length. sizeof(RAWINPUT) will not be the correct size when the data field is of RAWHID type so how do you allocate a variable with automatic storage type that has the right size for the entire struct? You can get a header that has the size for the entire struct but how do you actually allocate storage space for the data without using malloc? I've seen some example code that used a char array but that violates aliasing rules and there are also alignment issues with that approach.
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Sep 14, 2014
#include<stdio.h>
#include<conio.h>
#include<string.h>
char str1[20], str2[20]="kent";
main() {
printf("Enter your Username: ");
scanf("%s",str1);
[Code] ....
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Feb 11, 2014
I am getting a message from the palysound function it says File format not recognized i have linked the the compiler (i.e. dev c++) to the sound.
#include <cstdlib>
#include <iostream>
#include <stdio.h>
#include <conio.h>
#include <windows.h>
using namespace std;
int main(int argc, char *argv[]) {
[code]....
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Mar 1, 2013
so i need to encrypt a txt document using Caesar encryption. however i don't know how to open a txt and shift the keys into a new txt. the program has to ask the user for the number it should shift. Using arrays, if else. i also need to make a menu so i am using switch.
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Jun 8, 2013
I'm having some trouble with my binary tree for school. It is a data structures class so we are working on learning how to make our own binary trees and encrypt messages. Everything so far is working, except for my delete node function. I'm trying to do it recursively. Parts of my code.
/******** Node *********/
struct node {
char data;
node* right;
node* left;
};
/******** Binary Tree Class *********/
class BinaryTree
[Code]...
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Apr 14, 2013
I am trying to encrypt a char Array with binary data.
I think I understand the basic of Encryption / Decryption but I fail to see how to implement something.
I am trying to have a "key" that needs entered so the data can become readable executable. The program I am encrypting is a small console window with a message with the text "A secret message from your friend" (Not that it matters).
I have the binary data witch I can copy and what not. But how go about Encryption and then decrypt it and not destroying the data.
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Sep 30, 2013
I need to create a function using rot to encrypt certain strings the function begins like this
#include "encrypt.h"
std::string encrypt (std::string text, int rot) {
for (int i
and ends like this
return NULL;
}
dont need to write the string encrypted and dont need to crate a decrypt function.
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Jan 5, 2015
I have got to create a program that will gather input from the user and then encrypt & decrypt those characters.
I'm not very confident at coding so I'm sure many parts of my code are written poorly and not following the best practice so I have written a simple version of an algorithm where the program simply adds/subtracts a value of 2 to/from the ASCII values but I have discovered the use of the rand() and srand functions but I'm unsure how to go about using them within both my encrypt and decrypt function as a single value (static variable?).
Here is my code in its entirety at the moment.
#include <iostream >
#include <iomanip>
#include <cstdlib>
#include <ctime>
#include <string>
#include <cstring>
#include <fstream>
using namespace std;
char getMenuSelection (char m);
void encrypt (char key[]);
void decrypt (char code[]);
[code]....
This code currently doesn't execute due to ' undefined reference to 'encrypt(char*) '
Question
I am asking how to generate the random number and incorporate this into my encrypt and decrypt functions.
1. Would the use of a static or global variable make this work as is?
2. Would I need to create separate class files for both functions?
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Feb 17, 2015
I am interested in creating a file of a given size and then randomly accessing the file to populate it. Is there a way to quickly create, for instance, a 4 GByte file in C++, initially populated with garbage?
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Aug 5, 2013
How to save the struct to file and then read it back from the file ?
Code:
#include <conio.h>
#include <stdio.h>
struct student {
int person;
int egn;
float AvergeGrade;
[Code] ....
Have average grade: %f", person[i].FirstName, person[i].LastName, person[i].egn, person[i].AvergeGrade);
}
//Save to file
getch ();
}
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Apr 6, 2014
I have this simple program below:
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct {
unsigned long long int address;
float current;
unsigned char pressure_units;
} sensor;
[Code]...
As you can see, it has stored the last struct in all three indexes of the array. Why?
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May 24, 2013
i having a code to pass in array as argument, but the length returned is 1. This is not match with the array size.
int Getsize(int Array[])
{
int len = sizeof(Array)/sizeof(int);
cout << len << "
";
}
int main()
{
int X[] = {45, 12, 54, 83, 41, 36};
getsize(X);
}
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Feb 9, 2014
Currently I am trying to convert RGB to HSL. Everything is working but the saturation value. It is always close to the correct value (usually less than 10 off). For example:
RGB:(196,72,84)
HSL:(354,-46,52)
Correct HSL(354,51,53)
CODE:
double s=0;
double l=0;
chroma=max-min; //works correctly
//LIGHTNESS
l=(max+min)/2;
//SATURATION
if(chroma==0) {s=0;}
else {s=chroma/(1-fabs(2*l-1));}
s=s*100.000000;
l=(l/255.000000)*100.000000;
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Apr 25, 2015
I am writing a program where I read in data from a file into an array and a 2D array. However, when I cout that data to insure that it was all read in correctly, I get only the first full line of that input file(where there are actually 25 rows and 12 columns).
What am I doing wrong or should be doing differently?
ifstream fin;
//open the input file
fin.open("store_data.txt");
//If input file was opened, read input file data into array and 2d array
if(fin){
[code]....
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Apr 25, 2013
I'm writing a program to read in a Master.txt file and then update it through a Transaction.txt file that contains various transaction types [Adds (A), Deletes (D), and Edits (E1-E4)]. The records in both files are in ascending order based on Item#. Ultimately, the original Master.txt and updated Master file (Master2.txt) will be merged to reflect all valid transactions, and an errorLog.txt file will be created to indicate all invalid transactions. I feel I have all of the code written correctly, but I am still getting errors on my operands and identifiers.
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
struct invRecord {
string delDate;
[Code] ....
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Aug 6, 2014
PROGRAM:-
#include<fstream.h> //for reading and writing files
#include<conio.h> //for clrscr()
#include<string.h> //for string characters
#include<stdio.h> //for gets and puts function
#include<process.h> //for exit function
#include<iomanip.h> //for setw function
#include<dos.h> //for delay and sleep function
void main()
{ char ch,c=0,che=16;
int i=1,j=16;
[Code] .....
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Oct 30, 2013
Were are to implement a method countValue() that counts the number of times an item occurs in a linked list. Remember to use the STL <list>
int countValue(list<int> front ,const int item);
Generate 20 random numbers in the range of 0 to 4, and insert each number in the linked list. Output the list by using a method which you would call writeLinkedList which you would add to the ListP.cpp.
In a loop, call the method countValue() , and display the number of occurrences of each value from 0 to 4 in the list.
Remember that all the above is to be included in the file ListP.ccp
The output should be:
2 3 4 0 1 0 2 4 2 3 3 4 3 3 3 0 0 2 0 2
0 : 5, 1 : 1, 2 : 5, 3 : 6, 4 : 3
but I am getting:
1 2 4 0 4 4 3 3 2 4 0 0 1 2 1 1 0 2 2 1
0 : 4, 1 : 5, 2 : 5, 3 : 2, 4 : 4,
Here is my code:
#include<iostream>
#include<list>
using namespace std;
[Code].....
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Oct 30, 2014
I'm doing a bitwise operations on 2 bytes in a buffer, then storing the result in a variable. However, I sometimes get a non-zero value for the variable even though I'm expecting a zero value.
The relevant portion of the code is as follows.
unsigned int result = 0;
long j = 0, length;
unsigned char *data;
data = (unsigned char *)malloc(sizeof(unsigned char)*800000);
[Code] ......
I'm expecting result to be zero when my data[j] and data[j+1] are 0xb6 and 0xab respectively, which is the case for most of the time. However, for certain values of j, my result is strangely not zero.
j = 62910, result = 64
j = 78670, result = 64
j = 100594, result = 64
j = 165658, result = 512
j = 247990, result = 128
j = 268330, result = 512
j = 326754, result = 1
j = 415874, result = 256
j = 456654, result = 1024
j = 477366, result = 512
It appears that these strange result values are all powers of 2, with a 1 bit appearing somewhere in the unsigned int.
I'm not changing the value of result anywhere else in the code, and when I print out (unsigned int)(((data[j]^0xb6)<<8)|(data[j+1]^0xab)), I get 0, but somehow when it gets stored in result, it's no longer zero.
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