assignment-operator

Boolean and String Overloads of the Assignment Operator (C++)

由 自古美人都是妖i 提交于 2019-12-01 03:41:57
问题 I am defining multiple overloads of the assignment operator as follows: Foo.h class Foo { private: bool my_bool; int my_int; std::string my_string; public: Foo& operator= (bool value); Foo& operator= (int value); Foo& operator= (const std::string& value); }; Foo.cpp // Assignment Operators. Foo& Foo::operator= (bool value) {my_bool = value; return *this;} Foo& Foo::operator= (int value) {my_int = value; return *this;} Foo& Foo::operator= (const std::string& value) {my_string = value; return

Scala multiple assignment to existing variable

由 六月ゝ 毕业季﹏ 提交于 2019-12-01 03:35:19
I can do something like def f(): Tuple2[String, Long] = ... val (a, b) = f() What about if the variables are already existing? I'm running the same sets of data over filters and I don't want to chain them (long names and such). This is what I tried, but it complains about expecting ; instead of = on the last line: var a = ...initialization for this data var b = ...some other init (a, b) = g(a, b) // error: expected ';' but found '=' Is there a way to avoid an intermediary tuple? As Alex pointed out, the short answer is no. What's going on with your code is this: when a and b are already bound

Parsing “->” assignment operator in R

由 丶灬走出姿态 提交于 2019-12-01 02:27:09
My question is about parsing expressions in R language. Let me jump right into an example: fun_text <- c(" 0 -> var f1 <- function() { 0 -> sum_var sum_var2 = 0 sum_var3 <- 0 } (function() { 0 -> sum_var sum_var2 = 0 sum_var3 <- 0 })->f2 f3 = function(x) { 0 -> sum_var sum_var2 = 0 sum_var3 <- 0 } ") fun_tree <- parse(text=fun_text) fun_tree fun_tree[[1]] fun_tree[[2]] fun_tree[[3]] fun_tree[[4]] After that, we obtain those results: expression(0 -> var, f1 <- function() { 0 -> sum_var sum_var2 = 0 sum_var3 <- 0 }, (function() { 0 -> sum_var sum_var2 = 0 sum_var3 <- 0 })->f2, f3 = function(x) {

Java - comma operator outside for loop declaration

由 元气小坏坏 提交于 2019-11-30 19:47:34
I know I can use the comma operator like this for (int i = 1, j = 15; j>10; i++, j--) { // do something neat } but some articles seem to suggest that the comma operator can be used outside of the for loop declaration, for example int j = 2, k = 4 ; int x ; // Assignment statement with comma operator x = j + 1, k ; source: http://www.cs.umd.edu/~clin/MoreJava/ControlFlow/comma.html or int x = (expression) ? (i++,2) : 3; source: https://stackoverflow.com/a/12047433/1084813 This would be a neat trick for a code obfuscation contest or to confuse my colleagues, but neither of the examples will

How to approach copying objects with smart pointers as class attributes?

由 99封情书 提交于 2019-11-30 14:27:24
From the boost library documentation I read this: Conceptually, smart pointers are seen as owning the object pointed to, and thus responsible for deletion of the object when it is no longer needed. I have a very simple problem: I want to use RAII for pointer attributes of a class that is Copyable and Assignable. The copy and assignment operations should be deep: every object should have its own copy of the actual data. Also, RTTI needs to be available for the attributes (their type may also be determined at runtime). Should I be searching for an implementation of a Copyable smart pointer (the

assignment operator within function parameter C++

由 早过忘川 提交于 2019-11-30 13:58:10
问题 I'm studying data structures (List, Stack, Queue), and this part of code is confusing me. ListNode( const Object& theElement = Object(), ListNode * node = NULL); template<class Object> ListNode<Object>::ListNode( const Object& theElement, ListNode<Object> * node) { element = theElement; next = node; } Why there are assignment operators within function parameters? What does Object() call do? 回答1: Those are not assignment operators. Those are default arguments for the function. A function can

`x = y, z` comma assignment in JavaScript [duplicate]

由 淺唱寂寞╮ 提交于 2019-11-30 13:45:45
问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Javascript syntax: what comma means? I came across the code while reading this article (do a Ctrl + F search for Andre Breton ): //function returning array of `umbrella` fibonacci numbers function Colette(umbrella) { var staircase = 0, galleons = 0, brigantines = 1, armada = [galleons, brigantines], bassoon; Array.prototype.embrace = [].push; while(2 + staircase++ < umbrella) { bassoon = galleons + brigantines;

Derived class inherit base class assignment operator?

由 房东的猫 提交于 2019-11-30 09:27:58
问题 It seems to me that Derived class don't inherit base class Assignment operator if Derived class inherit Base class assignment operator , can you please explain the following example In the following code I am overriding base class operator= in Derived, so that Derived class default assignment operator calls overloaded operator= #include <iostream> using namespace std; class Base { public: Base(int lx = 0):x(lx) { } virtual Base& operator=( const Base &rhs) { cout << "calling Assignment

assignment operator within function parameter C++

由 人走茶凉 提交于 2019-11-30 09:07:31
I'm studying data structures (List, Stack, Queue), and this part of code is confusing me. ListNode( const Object& theElement = Object(), ListNode * node = NULL); template<class Object> ListNode<Object>::ListNode( const Object& theElement, ListNode<Object> * node) { element = theElement; next = node; } Why there are assignment operators within function parameters? What does Object() call do? Charles Salvia Those are not assignment operators. Those are default arguments for the function. A function can have one or more default arguments , meaning that if, at the calling point, no argument is

What is the result of an assignment expression in C? [duplicate]

由 余生颓废 提交于 2019-11-30 08:47:51
This question already has an answer here: What does an assignment return? 5 answers In the following code: int c; while((c=10)>0) What does c = 10 evaluate to? Is it 1 which indicates that the value 10 is assigned to variable c successfully, or is it 10? Why? c = 10 is an expression returning 10 which also assigns 10 to c. Assignment returns with the assigned value. In case c=10 is 10. Since 10!=0, in c it means also true so this is an infinite loop. It is like you would write while(10) Plus You've made the assignment. If You follow this logic, You can see, that while(c=0) would be a loop that
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