I created a structure containing two variables of type char.
i.e. char name[64],char details[128];
And a pointer to structure now when I write this name and details to file and now I want to change the particular name.
i.e. To modify then if the stored file name is greater than the entered name then it is erasing the next record line also I need to allocate some memory.
I'm currently learning templates -- & my logic is in a knot with what I am trying to do which is the following:
-Create a function name load
-Accepts a filename (the filename is a text file of integers)
-Open the file
-Create an array(dynamically allocating an array) filling it with the elements read in from the file & returns the array(so that the return type of the array is a pointer to the element type of the array).
//Header file:
#ifndef BUBBLE_SORT_H
#define BUBBLE_SORT_H
#include <iostream>
template <typename T>
void load(std::string filename, T *&arr, int *size);
[code].....
how to allocate memory when it comes to using templates..
I am trying to make a function that allows me to allocate memory to a "mem" variable and setting each of its chunk's status to FREE. FREE is defined as 0. Below is my code of the function.
Code:
int allocate(mem *mm, int num_chunks, int chunk_size) {
int i;
mem *temp;
if((mm = (mem *) malloc((num_chunks + 1) * chunk_size)) == NULL){
perror("Failed to Malloc
[code]...
mem; If my function works the way it should, it should print out five 0 because that is how I set them in the function, but this is not the case. I've looked at my function for 2 hours, but I could not figure out any logical error. Now, I think my problem lies with my limited knowledge of pointer arithmetic. On the other hand, when I insert 1000 as the second argument into my function, it gives seg faults, which is not the case for smaller values like 5, 10, 15, etc.
what i want to do is if memory allocation fails it display a message shown in the example but its not working
vehiptr = new VEHICLE[vnum];
if(vehiptr == 0)
{
cout<<"Failed to Allocate Memory"<<endl;
return main();
}
I’m writing an application for raw image processing but I cannot allocate the necessary block of memory, the following simple code gives me an allocation error.
double (*test)[4];
int block = 32747520;
test = new double[block][4];
off course with smaller block size (i.e. int block = 327475;) it works fine. Is there an allocation limit? How it is possible to deal with big blocks of memory?
I CANT use std::string, classes, constructors for this project. I am required to use this archaic method of c-style strings with dynamic memory allocation occurring outside the struct.. i know its not the best way to go about this, but there's nothing i can go. I have a struct:
struct card {
char *suit;
char *rank;
int cvalue;
}
I've created a pointer of size 52 for my deck
card *deckPtr = new card[52];
card *deckHome = &deckPtr[0];
I then try to use
for(int i=0;i<52;i++) {
(*deckPtr).suit = new char[8];
(*deckPtr).rank = new char[7];
deckPtr++
}
deckPtr=deckHome;
I am essentially trying to fill in these arrays from a card file, but I cannot make it past running the program, i get sa seg fault which I dont understand why.
I dynamically allocate memory in my card read in function..
void cardInit(card *deckPtr) {
card *deckHome = &deckPointer[0];
ifstream fin;
char *finName = new char[13];
cin >> *finName
fin.open(finName)
[Code] ....
Its a pretty simple program..and my dynamic memory works for the file name, but I cant figure out why it doesnt work for structs?
There is a part in the lesson that explains how malloc is used to allocate free memory to a pointer and gives us 2 examples:
Code:
float *ptr = malloc( sizeof(*ptr) ); and Code: float *ptr;
ptr = malloc( sizeof(*ptr) );
From my logic in the first case we allocate the memory to *ptr and in the second to ptr.
It's a bit confusing, am I missing something?
Consider this program:
Code:
// sb_string class v1.04
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
typedef struct sb_string {
[Code] ....
And here is the output I got:
Code:
[harshvardhan@hari-rudra] ~/Desktop% gcc49 -o test test.c
[harshvardhan@hari-rudra] ~/Desktop% ./test
-before Value of len = 1
(in_function)-before Value of len = 1
(in_function)-after Value of len = 1
-after Value of len = 1 I was trying to make a little easier to work with string. Once the memory is allocated by malloc via sb_init() function, the sb_massacre function wasn't working to deallocate the memory. I had used multiple versions of gcc and clang but the result is same.
So my assignment is to create a program that calls for a function in main that dynamically allocates an array[3] and then have pointers with multiple levels of indirection and pass them by reference so they are not lost after the function. Here is my code:
#include <iostream>
#include <array>
#include <iomanip>
#include <string>
[Code]....
Next part is to ask user for two non-negative numbers and then get the length of those numbers and create an array. for the size of each number they input. Then to separate those numbers and add the cross-sums.
A special hardware unit with some storage in it is connected to your computer and is memory-mapped so that its storage is accessible in the address range 0x55500000 – 0x555fffff. You want to interface this hardware unit to your C++ program so that dynamic memory is allocated in this hardware unit, not in your computer’s memory. Implement a class MyHardwareMemAllocator which has the following function.
void * allocMemoryInMyHardware(int numberOfBytesToAllocate);
which returns a pointer to the allocated memory chunk, or null if unable to allocate.
C library calls like malloc are not allowed.
1) How to allocate memory from given address range.
2) How to check whether this required memory space is available or not for allocating
I use the array of Radiobutton,string,.. in my project. How i can destruct these array from memory,because i see the stackoverflew exception.
View 1 Replies View RelatedI have a question about the KLU library for LU factorization of sparse matrices. The KLU library accepts a pointer to a memory allocator function, by default it is malloc(). Then it uses this pointer to allocate the memory required.
I want to extend the library and I now have object of classes. I want to use the operator new instead of malloc to allocate the memory. In the same time I want the new operator to call the constructors of the objects. Is there a way to do it?
I want to edit the contents of a file using fstream, but none of the modes in the fstream constructor work for me.
If I use ios::trunc, then the whole file is deleted - but I want to retain the contents and edit it. If I use ios::app, then I can only add data to the end of the file - but I want to edit the data in the middle of the file. If I use ios::ate, then the whole file is deleted again, similar to ios::trunc.
How can I create an fstream object without deleting the contents of the file, whilst still being able to move the pointer arbitrarily around in the file with seekp() (and not just placing it at the end as with ios::app)?
A user enters a query and other users reply to it. But it creates a problem here. After adding queries, if I wish to reply to query in between then it adds a redundant entry in file. 1st entry is the original query without reply and 2nd entry is the same query now with a reply added. I want only 1 entry of the query along with replies.Here is the code:
Code:
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
#include "var.c"
int check_count();
void add_query();
void add_reply();
}
[code]....
I am trying to store each value of a column from a text file into an dynamically allocated array, which needs to be globally declared for further usage in the program.The input textfile contains the following:
34932 13854 13854 2012-01-07
172098 49418 53269 2012-01-07
I have written the following code:
Code:
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main()
}
[code]....
The commented printf line gives the entire values of the column, which proves that the file is correctly being read.But on compiling this program I get both compiler warnings and finally segmentation fault.
I've a problem here...
#include "stdafx.h"
#include <iostream>
#include <fstream>
#include <conio.h>
#include <string>
#include <iomanip>
using namespace std;
int _tmain(int argc, _TCHAR* argv[])
[Code] ....
The program needs to be able to read the middle names within the text file named Info2.txt
Simply adding the Mname or any related value where the other to name values doesn't do anything and only the 1st line appears on the output.
Don Jon111012
Jack Bo Todd151015
Jill Jo Jane161011
Bob Jack Chuck 131513
Da Fu111012
That is the correct way it appears in the text file. Also I know it's commented out, but that just to keep the program from crashing.
current output
Survey Results:
Name Results
Don Jon 33.00
This is the Info1.txt file info by the way.
Ken A202017
Gus B151015
Bill C151512
Jara C151720
Lu E101510
Chow B171015
And the output
Survey Results:
Name Results
Ken A 57.00
Gus B40.00
Bill C42.00
Jara C52.00
Lu E35.00
Chow B 42.00
Which when ran with Info1 selected, it is the correct output I'm looking for. I've tried getline and other solutions and they didn't work.
In c++ ., I am getting unable to get obj file error first time i compiled i got the output but during the 2nd time i got this error .....
View 1 Replies View RelatedReading a .dat file, i'm unable to open the file. This program is for a Air Quality index detector, the AQI machine records the particle concentration every minute and saves it into new data file for each day. So I need to make this program run every minute and convert the concentration in to the AQI readings.
The filename is of the format "ES642_2013-11-09.dat", where ES642 is the software name of the machine, and rest is the year, month and day. The code here is just for the file reading section:
Code:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
[Code] .....
Code:
'test.exe': Loaded 'C:UsersPcDocumentsVisual Studio 2010Projects estDebug est.exe', Symbols loaded.
'test.exe': Loaded 'C:WindowsSysWOW64
tdll.dll', Symbols loaded (source information stripped).
'test.exe': Loaded 'C:WindowsSysWOW64kernel32.dll', Symbols loaded (source information stripped).
[Code]...
The thread 'Win32 Thread' (0x2d0) has exited with code 1 (0x1).
The program '[6040] test.exe: Native' has exited with code 1 (0x1). my code is not wrong but there is an error which ı dont understand ...where is my error?
here is my code, I'm trying to read a .txt file into a 2D array... what's wrong with my code?
Code:
#include <stdio.h>
#define INPUT_FILE_GET_NAMES "names.txt"
#define INPUT_FILE_GET_SALES "sales.txt"
#define MAX_ROWS_NAMES 25
#define MAX_COLS_NAMES 20
#define MAX_ROWS_SALES 25
#define MAX_COLS_SALES 6
//Function Declarations
char getNames(char namesArray[][MAX_COLS_NAMES], char filename[]);
[Code]...
Need reading a .dat file, i'm unable to open the file
This program is for a Air Quality index detector, the AQI machine records the particle concentration every minute and saves it into new data file for each day. So I need to make this program run every minute and convert the concentration in to the AQI readings.
The filename is of the format "ES642_2013-11-09.dat", where ES642 is the software name of the machine, and rest is the year, month and day.
The code here is just for the file reading section:
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
int main(int argc, const char * argv[]) {
[Code] ....
I'm having some problems with Input to an array from a file. I think that i need to make a new array for every instance of the loop but i can't figure out how.
Participator class
void Participator::read(ifstream &stream){
getline(stream, name);
getline(stream, address);
stream >> paid;
}ParticipatorRegister class
void ParticipatorRregister::readFromFile(){
[Code]...
my programme showing error 'unable to open inclde file ****' i fallowed the general procedure i.e., options-->directories--> ( inclde proper path) still not working..
View 2 Replies View RelatedI've been trying to read a .txt into a linked list in the attached code. I'm running into problems, specifically I'm getting errors on line 41 (curr->word=charTemp. I'm trying to set the word array equal to the charTemp array. I've tried strcpy with no luck .
Code:
#include <stdio.h>#include <stdlib.h>
#include <string.h>
//Struct for linked list
typedef struct node {
char word[25];
struct node *next;
} node;
[Code]...
I'm trying to upload a file to a FTP server with curl. The problem is that I do not know what to do after I enter the passive mode and open the specified port. I tried to send data with curl_easy_send but it simply hangs.
bool Ftp::Upload(const char *local_fn,const char *remote_fn)
{
int ret;
string ip;
unsigned port;
SendCmd("TYPE I");
// Enter passive mode and get IP & port
if(pasv(ip,port)==false)
return false;
[Code]...
How to send file to the server. And I also suspect I should tell the file size to the server.
I am trying to take text from a file and have it displayed using fprintf at line 46. When I run the below code nothing prints out. My text file has 4 lines with 5 different strings separated by whitespace.
#include <cstdlib>
#include <vector>
#include <cstring>
#include <stdlib.h>
#include <errno.h>
#include <stdio.h>
using namespace std;
//declare my own struct
[Code]...