Tutorial by Examples: n

This method gets the user agent and parses it to find the browser. The browser name and version are extracted from the user agent through a regex. Based on these two, the <browser name> <version> is returned. The four conditional blocks following the user agent matching code are meant t...

When you are copying a string into a malloced buffer, always remember to add 1 to strlen. char *dest = malloc(strlen(src)); /* WRONG */ char *dest = malloc(strlen(src) + 1); /* RIGHT */ strcpy(dest, src); This is because strlen does not include the trailing \0 in the length. If you take the ...

A programming best practice is to free any memory that has been allocated directly by your own code, or implicitly by calling an internal or external function, such as a library API like strdup(). Failing to free memory can introduce a memory leak, which could accumulate into a substantial amount of...

char buf[8]; /* tiny buffer, easy to overflow */ printf("What is your name?\n"); scanf("%s", buf); /* WRONG */ scanf("%7s", buf); /* RIGHT */ If the user enters a string longer than 7 characters (- 1 for the null terminator), memory behind the buffer buf will be...

If realloc fails, it returns NULL. If you assign the value of the original buffer to realloc's return value, and if it returns NULL, then the original buffer (the old pointer) is lost, resulting in a memory leak. The solution is to copy into a temporary pointer, and if that temporary is not NULL, th...

Detailed instructions on getting asp.net-mvc-4 set up or installed.

To get the size of a communicator (e.g. MPI_COMM_WORLD) and the local process' rank inside it: int rank, size; int res; MPI_Comm communicator = MPI_COMM_WORLD; res = MPI_Comm_rank (communicator, &rank); if (res != MPI_SUCCESS) { fprintf (stderr, "MPI_Comm_rank failed\n"); ...

Before any MPI commands can be run, the environment needs to be initialized, and finalized in the end: int main(int argc, char** argv) { int res; res = MPI_Init(&argc,&argv); if (res != MPI_SUCCESS) { fprintf (stderr, "MPI_Init failed\n"); exit (...

Floating point types (float, double and long double) cannot precisely represent some numbers because they have finite precision and represent the values in a binary format. Just like we have repeating decimals in base 10 for fractions such as 1/3, there are fractions that cannot be represented fini...

PREPARE prepares a statement for execution EXECUTE executes a prepared statement DEALLOCATE PREPARE releases a prepared statement SET @s = 'SELECT SQRT(POW(?,2) + POW(?,2)) AS hypotenuse'; PREPARE stmt2 FROM @s; SET @a = 6; SET @b = 8; EXECUTE stmt2 USING @a, @b; Result: +------------+ |...

You can get the value of an entry in the dictionary using the 'Item' property: Dim extensions As New Dictionary(Of String, String) From { { "txt", "notepad" }, { "bmp", "paint" }, { "doc", "winword" } } Dim program As St...

One of the most common things you'll need to do in the command prompt is navigate your file system. To do this, we'll utilize the cd and dir keywords. Start by opening up a command prompt using one of the methods mentioned here. You most likely see something similar to what's below, where UserNam...

WebGL is a browser technology so there isn't much to set up other than to have a browser. You can get started with WebGL on JSFiddle or Codepen or JSBIn or any number of other sites that let you edit HTML, CSS, and JavaScript online though there will be a few limitations (see below). You can also ho...

Two terms may be compared via the standard ordering: variables @< numbers @< atoms @< strings @< structures @< lists Notes: Structures compare alphabetically by functor first, then by arity and lastly by the comparison of each argument. Lists compare by length first, t...

The pickle module implements an algorithm for turning an arbitrary Python object into a series of bytes. This process is also called serializing the object. The byte stream representing the object can then be transmitted or stored, and later reconstructed to create a new object with the same charact...

Mutex locking in Go allows you to ensure that only one goroutine at a time has a lock: import "sync" func mutexTest() { lock := sync.Mutex{} go func(m *sync.Mutex) { m.Lock() defer m.Unlock() // Automatically unlock when this function returns // D...

Using the calendar module import calendar from datetime import date def monthdelta(date, delta): m, y = (date.month+delta) % 12, date.year + ((date.month)+delta-1) // 12 if not m: m = 12 d = min(date.day, calendar.monthrange(y, m)[1]) return date.replace(day=d,month=m, year=...

#include <stdlib.h> #include <stdio.h> int main(void) { result = EXIT_SUCCESS; char file_name[] = "outbut.bin"; char str[] = "This is a binary file example"; FILE * fp = fopen(file_name, "wb"); if (fp == NULL) /* If an erro...

To install v6.x update the packages curl -sL https://deb.nodesource.com/setup_6.x | sudo -E bash - Using the apt package manager sudo apt-get install -y nodejs

Download driver via nuget. Using this command in the package manager console Install-Package mongocsharpdriver