My program needs to receive data continuously from one process and the received data is read continuously by another process.But when I am trying to create a pipe using mknod on fat32 file system in linux , it throws an error saying "mknod: operation not permitted".
View 3 RepliesI am doing a project which I have to read, write and erase data from a NorFlash Memory. Then, I have to compare those data files in order to find errors.
Besides, I would like to know which is the best way to TEST errors in this kind of memories.
I am using NetBeans 7.3.1 for writting the code and Cygwin running on Windows XP Virtual Machine. The Memory Flash (S29JL064J 64 Megabit) is incorporated on an external board which is connected to an adapter board (using HDMI cable). This adapter is connected to the Laptop (using an USB).
How can I erase the data stored in /tmp/a.txt after every run of this code?
Code:
#include <stdio.h> // IO operations
#include <unistd.h> //for pid, ppid, fork functions
#include <sys/types.h> //for pid_t type, kill function
#include <stdlib.h> //for exit function
#include <signal.h> //for kill function
#include <sys/types.h>
#include <sys/stat.h>
[Code]...
I receive a telegram in XML format and I need to parse it and send my data in the same format back. My main problem is that I'm not allowed to use any open source software or other 3rd party software except VS2010. I have to write it in C++.
Now my question: is there any good tutorial for such a parser? I was hoping that I could write something which can be used similar to the GEtPrivateProfil-functions which are handy for ini-files.
My XML telegram looks like hat:
Code:
<Tag0 cmdId=“254“ version=“1“ ID=“87951“ action=“doing1“>
<!—comment1 -->
<Tag1 lId=“31“ type=“12“ index=“100“ state=“open“ />
<Tag1 lId=“31“ type=“12“ index=“135“ state=“open" />
<!—comment2 -->
<Tag2 lId=“42“ type=“32“ index=“2“ state=“open" >
<param key=“pos“ value=“center“ />
<param key=“car“ />
</epr>
</Tag0>
I was hoping to find a way to get to know how many tag1 and tag2 are in tag0 and then get for each tag the attributes and sub-tags like param in tag2
I am writing a program where I need to read a byte of char data and convert it into a text string of binary data that represents the hex value...
i.e. The char byte is 0x42 so I need a string that has 01000010 in it. I've written the following subroutine....
------------- My Subroutine ----------------------------------------------------------------------
void charbytetostring(char input, char *output){
int i, remainder;
char BASE=0x2;
int DIGITS=8;
char digitsArray[3] = "01";
[Code] ....
When I submitted the byte 0x42 to the subroutine, the subroutine returned to the output variable 01000010... Life is good.
The next byte that came in was 0x91. When I submit this to the subroutine I get garbage out.
I am using a debugger and stepped through the subroutine a line at a time. When I feed it 0x42 I get what I expect for all variables at all points in the execution.
When I submit 0x91 When the line remainder = input % BASE; gets executed the remainder variable gets set to 0xFFFF (I expected 1). Also, when the next line gets executed..
input = input / BASE; I get C9 where I expected to get 48.
My question is, are there data limits on what can be used with the mod (%) operator? Or am I doing something more fundamentally incorrect?
this is my read/write functions based the read from the last post! then went nuts with it! used the %19s%*s on the write to the file, solved all the probs on the read side! but any refining on this would be great. This is another program that i started with the forums, and started going my own direction!
Code:
void WriteAccount(int account,char *a[])
{
FILE *fptr;
char Memo[20];
char buff[20];
double Amount;
struct tm *sTm;
}
[code]....
the a[] is a string array with bank account names, and Account is the number on the menu based list.
I have two designs for reading/writing my classes to XML. Which do you think is better:
This is my structure (Attributes are single class members, Elements are std::vector< T > members
Structure:
+ Calibrator
+ Attrib: readLabel (string)
+ Attrib: saveLabel (string)
+ Element: Device
+ Attrib: sourceLabel (string)
+ Attrib: destLabel (string)
+ Element: CalPoint
+ Attrib: sourceVal (double)
+ Attrib: destVal (double)
1. Design 1: Have an independent class to handle everything and "friend" it with the users.
Pro: Only 1 interface needed and we can switch interface easily.
Con: There is a lot of inter-class data which destroys encapsulation
class CalibratorXML;
class Device{
string sourceLabel;
string destLabel;
vector<CalPoint> calPoints;
friend class CalibratorXML;
[Code] .....
I am planning to use this mostly to copy binary files, but why won't this work with text???
input.txt
int main(int argc, char* argv[]) {
// open file
std::ifstream ifs;
ifs.open("./input.txt", std::ios::binary);
[Code] ....
output.txt
310^?z^@^@^@^@^@300367346^A^@
Will this method always work to copy a file?
I'm looking to write a program in C/C++ to traverse a Fasta file formatted like:
>ID and header information
SEQUENCE1
>ID and header information
SEQUENCE2
and so on
in order to find all unique sequences (check if subset of any other sequence) and write unique sequences (and all headers) to an output file.
My approach was:
Prep: Copy all sequences to an array/list at the beginning (more efficient way to do this?)
Grab header, append it to output file, compare sequence for that header to everything in the list/array. If unique, write it under the header, if not, go on.
However, I'm a little unsure as to how to approach reading the lines in properly. I need to read the top line for the header, and then "return?" to the next line to read the sequence. Sometimes the sequence spans more then two lines, so would I use > (from the example above) as a delimiter? If I use C++, I imagine I'd use iostreams to do the reading.
How to read some characters from file, I know we can move a pointer to some position using seekg() & seekp() function, get current position of the pointer through tellg() & tellp() functions. By moving the pointer to appropriate position using seekg(), we can read the whole line using getline() function. But is there any function which read certain characters from the current position of the pointer and write certain characters from current position of the pointer.
View 1 Replies View RelatedHow to read some characters from file, I know we can move a pointer to some position using seekg() & seekp() function, get current position of the pointer through tellg() & tellp() functions. By moving the pointer to appropriate position using seekg(), we can read the whole line using getline() function. But is there any function which read certain characters from the current position of the pointer and write certain characters from current position of the pointer.
View 3 Replies View Related#include <stdio.h>
#include <stdlib.h>
int main () {
FILE * pFile;
long lSize;
char * buffer;
size_t result;
pFile = fopen ( "myfile.bin" , "rb" );
[Code] .....
How to open binary for read and write? Why the buffer is char * buffer? i mean in binary u cant read chars . How can it be? how the data is represented? just like txt file? What the buffer will contain how to print this buffer???
reading and writing 2D arrays I've been trying out a few tutorials using FileStream but I couldn't get any of them to work.
Anyway what I'm trying to do is save the playerArray to a .txt file and then read from that .txt into the fields within the GUI. This is supposed to act as a database.
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
[Code]....
the output of the password text file contains like this:
username
776655443322 (password encoded)
How to write the value in last line (3rd row) of the file. after that read and write or alter 3rd row value. I need logic using "C" language.
Explain me a working code to read and write a file using serial communication.and i need to store that file.I know normal file handling in C, but how it is through serial port i am not getting.
View 1 Replies View Relatedcalled object 'fptr_in' is not a function or function pointer
called object 'fptr_out' is not a function or function pointer
what can i do for the errors?(i mustn't use loop and arrays for the code)
Code:
#include <stdio.h>
void sum_of_2nd_and_3nd( FILE* fptr_in, FILE* fptr_out);
int main()
return 0;
}
void sum_of_2nd_and_3nd( FILE* fptr_in, FILE* fptr_out){
}
[code].....
I'm not sure if I should do this with malloc or a char array. What I need to do is create 4 methods to read and 4 to write to memory like this (and it has to be fast):
Code:
char GetByte(char* memory, int offset);
uint16 GetInt16(char* memory, int offset);
uint32 GetInt32(char* memory, int offset);
char[] GetString(char* memory, int offset);
So basically memory is the malloced memory and the offset is the position I want to read at.
I'm not sure if there's already a way to do this and maybe I'm overlooking something.
So I've been turning my programs into classes and I run into errors.
So this program is supposed to allow the user to open the file and either read or write to it.
I've omitted the read part from it as I want to attempt that on my own .
I get these compile errors:
fileclass.cpp:13: error: ISO C++ forbids declaration of ‘choice’ with no type
fileclass.cpp:21: error: ISO C++ forbids declaration of ‘choice’ with no type
fileclass.cpp: In member function ‘int file::choice()’:
[Code] .....
I would like to read in binary files, then write them to another file.
I write a code, what works perfectly, if I would like to just copy the file to another. But I want to make it a little other.
If I open a file in hex-editor I also can see the ASCII values. But I would like get the ONLY the hex values to the other file.
For example:
d5 57 4f ad 30 33 0b 4e 49 a7 05 18 c4 90 66 d8 45 ac 39 3e 7d f1 a8 02 80
14 20 90 6e 20 12 38 0c 65 4a 28 d2 80 72 04 20 a9 4a 82 84 60 6a 0b 25
59 4c 30 c8 69 c0 ec fa 36 ed 3a da b1 9a 82 02 e0 bb 7e 41 87 02 f6 10 34
eb 95 93 63 01 6b 8d e1 d7 43 c3 df 92 5d 8a ed 57 61 4e 36 07 2a d7 56 2b
b5 0e 55 83 b4 76 8c b7 61 77 0e c9 76 0c 81 1b 01 63 0c 8b 73 57 d5 6d 4c
0c c2 0d 52 45 18
How could I make it?
So I'm trying to create a program that allows one to read/write on to output.txt. I though I had everything set up right, but its only writing one word to the text file. Heres the code.
#include "stdafx.h"
#include <iostream> //Needed for User Input
#include <fstream> //needed for ofstream
#include <string> // needed for strings
#include <windows.h> //needed for Sleep
#include <cstdlib> //Needed for return EXIT_SUCCESS;
using namespace std;
int main() {
ofstream outputfile; //allows to read and write to files
[Code] .....
If I type Puppies Are Cute and go to output.txt, the only thing written in the text file is Puppies.
need to create a program for the following problem
1.Program takes messages as input at a rate “X” msg/sec, and outputs those messages at “Y” mgs/sec in a file.
2.The peak value of X can be 10msg/sec, and Y can be at max 5msg/sec. System should be designed in such a way that it can handle the peak input rate of 10msg/sec for not beyond 5 minutes.
3.Message contains following fields – unit id, timestamp, temperature.
4.Input data to be read from a file. Output data to be written to a file.
5.For testing design 3 types of profiles –
a.Profile 1 for 10 min – low rate, i.e. X = 4 msg/sec on an average throughout the period.
b.Profile 2 for 10 min – Max rate, i.e. X = 10 msg/sec for 2 min; then a sleep of 2 min, then repeat the same pattern till complete period
c.Profile 3 for 10 min - Max rate, i.e. X = 10 msg/sec for 5 min; then no traffic for next 5 min
I have looked through te tutorials here, and even google it, as well as tried to follow the power points from my class..but I still can't seem to figure out how to make this code work correctly.. Basically I have to create a file called grade and write to it a student name and their grade score, and then read from the file all students names and there grade and display this on the screen as well as calculate the grade average for all of the students and display it.
Well I am able to write to the text file, but I can't seem to get the rest to work. I can't figure out how to read from the text file..Here is my code below.
write a sample code that does something similar write to text file string and numbers and then reads from it.
#include <iostream>
#include <fstream>
using namespace std;
[Code].....
I decided I wanted to make a proper programming language with a virtual machine and bytecode. I used this tutorial: [URL] .....
As a starting point for my project. So far I have modified it to allow for 32-bit addressing so that I can theoretically use 4GB in my programs. Now the problem I'm having is creating the memory.
Question:
I'm not sure if I should do this with malloc or a char array. What I need to do is create 4 methods to read and 4 to write to memory like this (and it has to be fast):
char GetByte(char* memory, int offset);
uint16 GetInt16(char* memory, int offset);
uint32 GetInt32(char* memory, int offset);
char[] GetString(char* memory, int offset);
So basically memory is the malloced memory and the offset is the position I want to read at.
correct the below code:
file already contains entries : 1st row username; 2nd row password.
check status required to write at third line and need to read or alter the check status value.
Currently this code is working if already there is a value for check status, then it is overwriting else UI hanging.
Code:
WriteCheckStatusToFile(BOOL& locVar) {
FILE *l_pFile = NULL;
CString l_strRememberCheck;
l_strRememberCheck = GetExePath() + _T("password");
CString sVar;
sVar.Format(_T("%d"),locVar);
[code]....
I want to read and write value on serail port to Microcontroller with MFC. The MFC have no serial port tool like in VB Professionnal edition. I try to find MFC connect serial port example but I not found. If you have good example for read and write on serial port with MFC
View 2 Replies View RelatedI have a binary tree, and I want to store all information its leaves stores into a binary file and then read it.
What I tried:
A function that reads the tree, and whenever it finds a leaf, it writes in the binary file:
Code:
[...]
if(tree->right == NULL && tree->left == NULL){
fwrite(tree, sizeof(tree), 1, output);
}
[...] a
And in the main function:
Code:
[...]
for(i=0;i<5;i++){
fread(tree, sizeof(tree), 1, output);
printf("This is the leaf number %d", tree->num);
}
[...]
I'm trying to read 5 nodes just to see if its working but it isn't. The output shows the first node of the tree everytime.