I have something I need a 2D array for, but for better cache performance, I'd rather have it actually be a normal array. Here's the idea I had but I don't know if it's a terrible idea: const int XWIDTH = 10, YWIDTH = 10; int main(){ int * tempInts = new int[XWIDTH * YWIDTH]; int ** ints = new int*[XWIDTH]; for(int i=0; i<XWI...
I'm writing a program and I have the following problem: char *tmp; sprintf (tmp,"%ld",(long)time_stamp_for_file_name); Could someone explain how much memory allocate for the string tmp. How many chars are a long variable? Thank you, I would appreciate also a link to an exahustive resource on this kind of information. Thank you UP...
I have a collection of webapps that are running under tomcat. Tomcat is configured to have as much as 2 GB of memory using the -Xmx argument. Many of the webapps need to perform a task that ends up making use of the following code: Runtime runtime = Runtime.getRuntime(); Process process = runtime.exec(command); process.waitFor(); ... ...
I am trying to deal with a very large dataset. I have k = ~4200 matrices (varying sizes) which must be compared combinatorially, skipping non-unique and self comparisons. Each of k(k-1)/2 comparisons produces a matrix, which must be indexed against its parents (i.e. can find out where it came from). The convenient way to do this is to...
#include <cstdlib> #include <iostream> #include <boost/bind.hpp> #include <boost/asio.hpp> using boost::asio::ip::tcp; class session { public: session(boost::asio::io_service& io_service) : socket_(io_service) { } tcp::socket& socket() { return socket_; } void start() { socket_....
The following piece of code gives a segmentation fault when allocating memory for the last arg. What am I doing wrong? Thanks. int n_args = 0, i = 0; while (line[i] != '\0') { if (isspace(line[i++])) n_args++; } for (i = 0; i < n_args; i++) command = malloc (n_args * sizeof(char*)); ...
I'm building an application which will have dynamic allocated objects of type A each with a dynamically allocated member (v) similar to the below class class A { int a; int b; int* v; }; where: The memory for v will be allocated in the constructor. v will be allocated once when an object of type A is created and will never need t...
I'm studying for a final exam and I stumbled upon a curious question that was part of the exam our teacher gave last year to some poor souls. The question goes something like this: Is the following program correct, or not? If it is, write down what the program outputs. If it's not, write down why. The program: #include<iostream.h>...
I tried looking up other issues but couldn't find anything to match so here goes: I'm trying to display text in the table view so I use this bit of code: // StockData is an object I created and it pulls information from Yahoo APIs based on // a stock ticker stored in NSString *heading NSArray* tickerValues = [heading componentsS...
Hi here is my code. I want to dynamincly change no of elemnts in table with structs __state: typedef struct __state{ long int timestamp; int val; int prev_value; }*state_p, state_t; int main(int argc, char **argv){ int zm; int previous_state = 0; int state = 0; int i = 0; int j; state_p st; //her...
Hello guys, I am new to iPhone sdk and can't figure out why my application crashes. In the .h I have: UIImage *myimage; //so as it can be used as global -(IBAction) save; @property (nonatomic, retain) UIImage *myimage; In the .m I have: @synthesize myimage; - (void)viewDidLoad { self.imgPicker = [[UIImagePickerController alloc] ...
I've been reading up on C++ on the Internet, and here's one thing that I haven't been quite able to find an answer to. I know that static variables used within functions are akin to globals, and that subsequent invocations of that function will have the static variable retain its value between calls. However, if the function is never c...
Hi, Is there a simple, efficient Map implementation that allows a limit on the memory to be used by the map. My use case is that I want to allocate dynamically most of the memory available at the time of its creation but I don't want OutOFMemoryError at any time in future. Basically, I want to use this map as a cache, but but I wanna a...
I have to create a set of wrapping C++ classes around an existing C library. For many objects of the C library, the construction is done by calling something like britney_spears* create_britney_spears() and the opposite function void free_britney_spears(britney_spears* brit). If the allocation of a britney_spears fails, create_britney_...
Hello, I'm testing my App and in a very simple view, each time a tap on a UITableView row, my allocation overall bytes get higher and higher and never go downs. I don't have any special code there, so I created a new project from scratch with a very simple view, force one section and just three rows. In the didSelectRowAtIndexPath code...
Hi All, I have a "small" table of 60400 rows with zipcode data, 6mb in total. I want to iterate through them all, update a column value, and then save it. The following is part of my Zipcodes model which extends My_Db_Table that a totalRows function that - you guessed it.. returns the total number of rows in the table (60400 rows) pub...
In several pieces of sample objective-c code I've seen people create new objects like this: RootViewController *viewController = [[RootViewController alloc] init]; self.rootViewController = viewController; // self.rootViewController is a (nonatomic,retain) synthesized property [viewController release]; [window addSubview: [self.rootVie...
I've got the situation where the cycle of loading and then closing a document eats up a few Mb of RAM. This memory isn't being leaked as something owns it and cleans it up when the app exits (Visual Leak Detector and the Mac Leaks tool show agreement on this). However, I'd like to find out where it's going. I'm assuming it's some sort...
My app is allocating a ton of objects (>1mln per second; most objects are byte arrays of size ~80-100 and strings of the same size) and I think it might be the source of its poor performance. The app's working set is only tens of megabytes. Profiling the app shows that GC time is negligibly small. However, I suspect that perhaps the al...
I've been working on this program for five months now. Its a real time application of a sensor network. I create several linked lists during the life of the program and Im using malloc for creating a new node in the link. What happens is that the program suddenly stops or goes crazy and restarts. Im using AVR and the microcontroller is A...