Will the realloc just reduce the allocated size and keep the same pointer, or can there be a chance of it finding another place for that allocation ( Meaning that it will expensively move the memory to another location )?
I am trying to create efficient programs by making my dynamic allocations the least resource hungry as possible during runtime.
i want to improve my knowledge about the dyn allocation of char pointers... with this code i wanted to type a string and insert the string in a array created dynamically:
Code:
#include <stdio.h> #include <stdlib.h> #include <string.h> int main() { char c; char *test=NULL; unsigned int len; }
[code]....
why there are these 3 initial character '' ')' ':' that i didn't have typed...
I would like to realloc a 2D array. I have a counter, itime, it increases each step. Each step, I would like to reallocate my array, keeping the old values, and add new values to the array. When itime=1, I use only malloc, because it is allocated for the first time. When itime increases (e.q. itime=2), realloc comes into process. In the realloc process the GUI crashes.
how to correctly use realloc on an array of char arrays? Say I want to store strings in arrays (=array of char arrays) and double the size of max. strings (y value):
Code:
int x=200; int y=10; char *carray[y]; for (int j = 0; j < y; ++j) carray [j] = malloc (sizeof(char)*x);} }
I had a quick question regarding a program I am trying to complete. I have the basics worked out, and everything seems to be done, but I am running into two issues.
1= The program keeps telling me "Run-Time Check Failure #3 - The variable 'order' is being used without being initialized." and 2= When I reach my output screen I receive "Unhandled exception at 0x7751c41f in CISC 192 Project 3.exe: Microsoft C++ exception: std:Out_of_range at memory location 0x002eefb8.."
While the first one isn't necessarily a deal breaker the second one definitely is.
Code: // Bookstore Project 3.cpp : Defines the entry point for the console application. // Declarations #include "stdafx.h" #include <iostream> #include <iomanip> #include <cstdlib> #include <string> #include <istream>
I'm trying out the gmp library by building a simple pi calculation program (original, I know!). On a million digits of Pi I've debugged the program and seem to have about a megabyte too much of memory at the end of the program (I start with around 250k before any allocation begins and end at around 1200).
int main(int argc, char *argv[]) { //set a// int digitsofpi =1000000; mpf_set_default_prec(log2(10) *digitsofpi );
I am looking for a way to run a process form memory, without having any executable. The application will be kept inside a resource and will be extracted during run time. It should be then started as a new process. I couldn't find a solution that works also on x64
We have a proprietary third-party library that we make calls into via an API. Through a series of API calls, this library manipulates specific sets of data. Prior to making these calls, there are some API calls that are necessary in order to initialize the library in preparation for a specific set of data. One of the calls tells the library to allocate some memory and then perform whatever initialization is required. This particular API call returns a pointer to char (char*) that is later used as an argument for a few other API calls. My question is... Is there a way, or maybe some kind of trick, to tell exactly how much memory was allocated? It doesn't matter whether or not the solution (if there is one) is C++ related, or some series of OS commands. FYI: We're running on Redhat Linux 6.2 and using GNU C++ 4.4.6.
Is there any way to read RAM memory directly. For say i want to access memory location 0x0100 to 0x120. How to do that. how to declare the variable, is it unsigned int. what is the type of read values it hex or ascii. how t cast it.
I have declared a global variable as pointer. The program performs certain number of iterations. After every iteration, the size of memory required for the pointer changes and this pointer variable is to be accessed by different functions. Now, here is my doubt:If I allocate the memory for this global variable in a function, will the contents of the memory be lost once I exit that function. In my opinion, it should not be the case as the dynamic memory allocation takes place in "heap" and should not be affected by the call of functions.
# include <stdio.h> # include <math.h> # include <stdlib.h> # include <malloc.h> }
[code]...
I am compiling it on a 64 BIT ubuntu machine having 64GB ram using gcc 4.6 compiler. I am getting the following output Error allocating memory. But (914*866*2724) is approximately 8 GB, Whats wrong with the code?
I am new to C++ language and I am still learning.I'm doing basic stuff to better understand dynamic memory. I was wondering why I keep getting memory issues.*/
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..
In the code below. I believe I am returning the memory location of the value I am looking for. How can get the value?
main.cpp
int choice = 0; PlayerMenu *newPM = new PlayerMenu; File *file = new File; // Menu for loading, creating or exiting the game choice = newPM->menuChoices();
PlayerMenu.cpp
[Code] ....
I am not sure how to deference the value so I can get at the value instead of the memory location.
Now, let's suppose that I instantiate an array of 100 elements of each class:
case1 c1[100]; case2<20> c2[100];
My question is this: will c2 occupy roughly half of the memory than c1?will the value c1.n be allocated 100 times, while the value c1.n wil be allocated only once?
I have a situation where map elements will be inserted all throughout a continuous loop. I know that there's no reserve function for maps like there are for vectors, but I know exactly the maximum amount of elements there will be in the map, I just don't know the value of each individual map.
Would it be possible if I just inserted the maximum amount of elements in the beginning of the program, and change the value of each/any individual element later on? For example:
std::map<int, std::string> map; //There will be a maximum of 200 elements in this map for (int i = 0; i < 200; i++) { map[i]; }
//Change the value of individual elements as I wish
Is it more efficient than initializing on declaration if initializing will be done often?