Function is a block of code which performs a specific task.

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4
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8answers
539 views

Confusion regarding def function within Python

I've been learning Python for about 2 months now (Started with Learn Python The Hard Way, now reading Dive Into Python), and within both books, I still seem to be confused over this one bit of code. ...
1
vote
2answers
104 views

Are there constraints for functions in structured programming?

I just talking with a colleague (University instructor) who teaches C (Fundamental of programming Course). He said I won't give score to a student, if he uses I/O (scanf or printf or cin count) in a ...
0
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1answer
56 views

Setting up folders and importing modules in Python

I'm building an app to automate some processes that are annoying to do by hand (looking in a file, taking certain information out of a file, building another file with that information). My project ...
8
votes
9answers
6k views

Why Java does not allow function definitions to be present outside of the class?

Unlike C++, in Java, we cannot have just function declarations in the class and definitions outside of the class. Why is it so? Is it to emphasize that a single file in Java should contain only one ...
0
votes
1answer
94 views

Haskell types for functions

I don't understand the answer to this question: Q: Can Haskell find a type for the function selfapply defined by: selfapply f = f f A: The function selfapply is not typeable in the simple system of ...
29
votes
4answers
23k views

Why store a function inside a python dictionary?

I'm a python beginner, and I just learned a technique involving dictionaries and functions. The syntax is easy and it seems like a trivial thing, but my python senses are tingling. Something tells me ...
14
votes
8answers
8k views

Feature vs. Function [closed]

Often I hear PMs (Project Managers) talk about feature and function. And I'm just so puzzled to differentiate them. Sometimes I think of a feature to be equivalent to a user story. Something like "As ...
0
votes
2answers
137 views

Is there a approximate string comparison function which is odd like mathematical functions are odd?

I say odd like a mathematical function, a mathematical function is odd if f(-x) = -f(x) I understand that comparing two strings may seem to have little to do with this, because the arguments cannot ...
12
votes
4answers
9k views

In C++ why and how are virtual functions slower?

Can anyone explain in detail, how exactly the virtual table works and what pointers are associated when virtual functions are called. If they are actually slower, can you show the time that the ...
1
vote
1answer
74 views

When should one create a new py-function rather than tweaking another one?

Me and a co-developer are arguing when it's wise to cast a new function rather than tweaking another one. By tweaking I mean an option or a hidden check in an existing function. The question could be ...
1
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2answers
217 views

Are any side effects not concrete side effects?

In Chapter 23 of "Object Oriented Software Construction" (1988), Betrand Meyer makes a distinction between side effects, concrete side effects, and abstract side effects. Meyer defines a side effect ...
26
votes
5answers
2k views

Method extraction vs underlying assumptions

When I split big methods (or procedures, or functions — this question is not specific to OOP, but since I work in OOP languages 99% of the time, it's the terminology that I'm most comfortable with) ...
1
vote
3answers
335 views

How are basic functions implemented in a programming language if they are not built in? [closed]

The lowest levels of a programming language's library functions are always obscure and often have no code that looks like it even remotely does anything. Some languages have these functions like ...
-5
votes
1answer
92 views

Is there is a way to pass more than one value to the calling function in c++? [closed]

I'm new at computer science and programming, Can any one give me a hand to know "Is there is a way to pass more than one value to the calling function in c++". Explain how?
0
votes
1answer
136 views

Can i create a function with variable parameters in C?

I've always wondered where a single function such as printf(); can take in variable parameters and provide the right results. For example, printf("Number is %d",a); which has two parameters, and ...
1
vote
2answers
47 views

Function that would output all distinct values in an array

I want to create a function that outputs the distinct values in a given array. For example, in the following sequence 2 2 1 1 5 2 , the distinct digits are 2 1 5. What I've done till now is: void ...
30
votes
1answer
2k views

Name for a Function which Returns its Arguments?

A function that does nothing, takes no arguments and returns nothing is traditionally called a noop, or no-op. An example of a noop is below: function noop(){} http://en.wikipedia.org/wiki/NOP So ...
2
votes
5answers
605 views

When, if ever, should I daisy chain functions?

I'll try to be as brief as possible in respect to your time. In a program divided up into many functions by which it is intended that they execute themselves one after another, when (if ever) is it ...
8
votes
5answers
2k views

When would dynamic scoping be useful?

With dynamic scoping, a callee can access the variables of its caller. Pseudo C code: void foo() { print(x); } void bar() { int x = 42; foo(); } Since I have never programmed in a ...
0
votes
3answers
81 views

What is the difference between a helper and a convenience function?

The title and the question are the same! The two seem the same to me: a convenience is a helper. A helper is a convenience. So when is it good to use the one or the other term?
-1
votes
1answer
376 views

Python: Faster to use global variable or pass as arguments to a function? [duplicate]

Hey so i was wondering which is the more efficient way, or better practice to do in this situation. 1, def function(): global number number += 2 Or 2, def function(number): return ...
36
votes
10answers
3k views

Why is Today() an example of an impure function?

It seems like, when reading something like this Wikipedia article about "pure functions", they list Today() as an example of an impure function but it seems pretty pure to me. Is it because there is ...
0
votes
2answers
45 views

Iterating a function with a static argument: Global functions + lambdas vs internal function?

I am never sure which of these is better form: Option A def a(x,y): def b(z): return z+y return map(b, x) print a([10,20], 5) Option B def b(z,y): return z+y def a(x,y): return ...
8
votes
4answers
356 views

why empty function are needed

I started learning python and I am wondering why empty function are needed in a programming language e.g. in python: def empty_func(): pass even in shell scripts empty function empty functions ...
3
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2answers
109 views

Strategies for parameter wrapping

Methods with many parameters are often sometimes unavoidable. In my own experience I often find this is the case for program entry points and complex mathematical procedures - where refactoring is ...
21
votes
4answers
12k views

Where should I put functions that are not related to a class?

I am working on a C++ project where I have a bunch of math functions that I initially wrote to use as part of a class. As I've been writing more code, though, I've realized I need these math functions ...
3
votes
4answers
455 views

int * vs int [N] vs int (*)[N] in functions parameters. Which one do you think is better?

When programming in C (or C++) there are three different ways to specify the parameter in a function that takes an array. Here is an example (implementing std::accumulate from C++ in C) that shows ...
89
votes
11answers
7k views

One-line functions that are called only once

Consider a parameterless (edit: not necessarily) function that performs a single line of code, and is called only once in the program (though it is not impossible that it'll be needed again in the ...
15
votes
1answer
3k views

Is there a difference between arguments and parameters?

It might be like this: Parameter means from the callers POV and arguments mean inside the procedure, or other way round. Or is there no difference? Update In Swedish we say "anropsparametrar" i.e. ...
13
votes
5answers
2k views

Why is *declaration* of data and functions necessary in C language, when the definition is written at the end of the source code?

Consider the following "C" code: #include<stdio.h> main() { printf("func:%d",Func_i()); } Func_i() { int i=3; return i; } Func_i() is defined at the end of the source code and ...
1
vote
1answer
65 views

Are there defined standards for argument sequence? [closed]

Say I have a function taking three arguments: a symbol (an alias for a class, method or function name) a mirror/reflection of a specific object a mirror/reflection of a class in general is there a ...
3
votes
3answers
292 views

When is inlining worth it?

Modern compilers often inline functions when they decide it is worth it. But here comes my question: how does one define if it is optimal to inline function at given time, or more important how to ...
1
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0answers
16 views

Hidden event handlers and their parameters

I'm having a bit of trouble understanding why has an event handler to be defined as a function. AFAIK, a function can be used as anonymous called procedure as event handler It defines a ...
1
vote
1answer
125 views

Use Generic of Specific Function names for similar objects

Is there a school of thought on putting focus on using generic names for functions, opposed to naming functions based on the things they do? Example Say we have a Bill / Price Sheet object, that has ...
0
votes
2answers
102 views

memory needed to store a function in javascript

I have been using sizeof.js to investigate the size of various objects in javascript. It appears from this that the size of a function is essentially zero bytes, regardless of how many instructions ...
1
vote
2answers
167 views

How does the CPU access the values of stack-allocated variables? [duplicate]

Consider the following C++ function: void doStuff() { Thing thingA; Thing thingB; thingA.doSomething(); // .. etc } During the execution of this function, variables thingA and ...
20
votes
8answers
4k views

What is the benefit of a function without parameters which only calls another function

A tutorial (for Javascript) I'm doing suggests we write a function like this one: function sayHello() { //Some comments explaining the next line window.alert("Hello"); } Other than ...
35
votes
12answers
4k views

Why do most programming languages have special keyword or syntax for declaring functions? [closed]

Most programming languages (both dynamically and statically typed languages) have special keyword and/or syntax that looks much different than declaring variables for declaring functions. I see ...
0
votes
2answers
132 views

Is there a way for Object 1 to call Object 2's enums in a function call?

For example, if I have two classes "Director" and "Follower". I want the Director to tell the follower where to go (ex: follower1.go(direction.LEFT)), and I want the Director to know what directions ...
0
votes
1answer
90 views

Why does this function work even though the vars are different

$inumber1 = 10; $inumber2 = 20; function add($number1, $number2) { echo $number1 + $number2; } add($inumber1, $inumber2); I'm learning PHP coding for the first time and I'm ...
2
votes
1answer
354 views

How do multiple levels of inheritance affect virtual function call overhead in C++?

I am considering using a class hierarchy with more than a single level of inheritance, where virtual member functions form a "chain", for example: struct Base { virtual void foo(); }; struct D1 : ...
0
votes
1answer
98 views

How to split a Service class in two but still use them like one?

I've got a class: AuthenticationService findLoggedInUser() Checks session if User is logged in. If not, check client persistent user login cookie and log in. loginUser($email, $pw, $remember = ...
14
votes
7answers
2k views

Function only returns unchanged parameter, useless?

I just found this function in the project I'm working at: -- Just returns the text unchanged. -- Note: <text> may be nil, function must return nil in that case! function Widget:wtr(text) ...
41
votes
9answers
5k views

Beginning a sentence with a function name? [closed]

Occasionally while typing something up that relates to a case-sensitive programming language I end up starting a sentence with a function name. Now the rules of English state that the first word in a ...
0
votes
1answer
313 views

Does this function do one thing only?

Is the following method considered to be doing one thing only? I'm wondering about that since it takes an optional argument. public function findErrors($name = null) { if ($name) { ...
9
votes
4answers
559 views

Are first-class functions a substitute for the Strategy pattern?

The Strategy design pattern is often regarded as a substitute for first-class functions in languages that lack them. So for example say you wanted to pass functionality into an object. In Java you'd ...
28
votes
8answers
6k views

Is splitting up a function into several inner functions an anti-pattern? [duplicate]

Imagine a long and complicated process, which is started by calling function foo(). There are several consecutive steps in this process, each of them depending on result of the previous step. The ...
0
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2answers
117 views

Should you avoid adding unecessary stack frames?

I have been working with laravel (PHP) recently, and there is an option when using their fluent ORM to define where clauses using closures. This gives us two, functionally equivalent, ways to specify ...
2
votes
2answers
170 views

Property or Method to obtain information about a collection?

Suppose I have a MyList class which extends ObservableCollection<MyObject> where MyObject has the Boolean Property Enabled. Let's say I want the number of MyObject objects that have the ...
5
votes
6answers
7k views

CoffeeScript and Named Functions

Elsewhere: an argument has arisen over the terminology of a named function in CoffeeScript. In particular somebody refereed to something like this foo = -> console.log("bar") as a named ...