The need for communications between tasks depends upon your problem: Some types of problems can be decomposed and executed in parallel with virtually no need for tasks to share data. These types of problems are often called embarrassingly parallel - little or no communications are required. For example, imagine an image processing operation where every pixel in a black and white image needs to have its color reversed.
Simple Report all non-const variables declared at namespace scope. Avoid singletons Singletons are basically complicated global objects in disguise. In a multi-threaded environment, the initialization of the static object does not introduce a race condition unless you carelessly access a shared object from within its constructor.
Note that the initialization of a local static does not imply a race condition. However, if the destruction of X involves an operation that needs to be synchronized we must use a less simple solution. If you, as many do, define a singleton as a class for which only one object is created, functions like myX are not singletons, and this useful technique is not an exception to the no-singleton rule.
Enforcement Very hard in general. Look for classes with names that include singleton. Look for classes for which only a single object is created by counting objects or by examining constructors. Make interfaces precisely and strongly typed Reason Types are the simplest and best documentation, have well-defined meaning, and are guaranteed to be checked at compile time.
Also, precisely typed code is often optimized better. That is error-prone and often verbose. Consider using a variant or a pointer to base instead. For generic code these Ts can be general or concept constrained template parameters. An int can carry arbitrary forms of information, so we must guess about the meaning of the four ints.
Most likely, the first two are an x,y coordinate pair, but what are the last two? Comments and parameter names can help, but we could be explicit: Hard to do well Look for member functions with many built-in type arguments.
State preconditions if any Reason Arguments have meaning that may constrain their proper use in the callee. The type system cannot easily and naturally express that, so we must use other means.
For now, we place it in the definition function body. Expects is described in GSL. Note Prefer a formal specification of requirements, such as Expects p.
Note Most member functions have as a precondition that some class invariant holds. That invariant is established by a constructor and must be reestablished upon exit by every member function called from outside the class.
The rules for passing pointers. Prefer Expects for expressing preconditions Reason To make it clear that the condition is a precondition and to enable tool use. This can make them hard to distinguish from ordinary code, hard to update, hard to manipulate by tools, and may have the wrong semantics do you always want to abort in debug mode and check nothing in productions runs?
Once language support becomes available e. Note Expects can also be used to check a condition in the middle of an algorithm. Note No, using unsigned is not a good way to sidestep the problem of ensuring that a value is nonnegative.
Enforcement Not enforceable Finding the variety of ways preconditions can be asserted is not feasible. Warning about those that can be easily identified assert has questionable value in the absence of a language facility. State postconditions To detect misunderstandings about the result and possibly catch erroneous implementations.
Note Postconditions are especially important when they relate to something that is not directly reflected in a returned result, such as a state of a data structure used.
Example Consider a function that manipulates a Record, using a mutex to avoid race conditions: Stating the postcondition would have made it clear:C Program to Find the Largest Two Numbers in a given Array Posted on November 7, by Manish. This is a C Program to calculate the largest of two numbers in a given Array.
This program will implement a one dimentional array, then compares the elements and finds which is the largest two element in a given array.
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This introduction to R is derived from an original set of notes describing the S and S-PLUS environments written in –2 by Bill Venables and David M.
Smith when at the University of Adelaide. We have made a number of small changes to reflect differences between the R and S programs, and expanded some of the material. Table of Content. C Program to print table of n and square of n using pow() C Program to find sum of two numbers; C Program to Calculate Area and Circumference of circle; Write a ‘C’ Program to compute the sum of all elements stored in an array using pointers.
C Program to compute sum of the array elements using pointers. C program for addition of two numbers using pointers. In our program, we have two integer variables x and y and two pointer variables p and q. Firstly we assign the addresses of x and y to p and q respectively and then assign the sum of x and y to the variable sum.
Given two variables, x and y, swap two variables without using a third variable. Method 1 (Using Arithmetic Operators) The idea is to get sum in one of the two given numbers.