1,200 questions
1
vote
1
answer
112
views
Pass mixed references to function: value for small types, and reference for large types
I want to define a templated function that admits parameters by value only when they are "cheap to copy" and by reference when they are not.
For example, given function F, the goal is to ...
- 1,411
0
votes
1
answer
70
views
How to assign a new object to a reference?
Why can't I do it like this in Go?
func do(m1 map[int]string) {
var m map[int]string = make(map[int]string)
*m1 = &m;
}
I have m1 map, which means I can now it's reference? How to assign ...
- 1,988
1
vote
2
answers
80
views
Comparing Swift's and Rust's function signatures
I want to check my understanding of how Swift and Rust handle function parameters.
From what I’ve seen, Swift has two main parameter modes:
Pass by value, immutable: f(x: T) and
Pass by reference, ...
- 11
4
votes
3
answers
212
views
why does getaddrinfo() take the node, service and hints arguments as pointers? [duplicate]
int getaddrinfo(const char *node, // e.g. "www.example.com" or IP
const char *service, // e.g. "http" or port number
const struct addrinfo *...
- 41
-5
votes
3
answers
113
views
How to fix printing declared function [duplicate]
I'm still new at functions and I tend to print the function which I don't know how to print the declared function. It prints "1" and not "John".
#include <iostream>
void ...
- 11
2
votes
4
answers
107
views
Iterating over an Array
I tried this block of code and it yields two different results
public class PassArrayToFunction {
public static void increase1(int[] arr){
for(int a: arr)
a += 1;
}
...
- 21
2
votes
3
answers
108
views
Pass "Slice" structs by value or by reference? [closed]
I have the following two structs. They are both "slices" in that they have a pointer to data and dimensions, but they do not "own" the data (they are not responsible for memory ...
- 51
0
votes
2
answers
63
views
Batch function get the value of variable pass by reference
In the below script, there is passed var1 by reference to myDosFunc, so it can change the value.
How can the value of the referenced variable be get within the function without having to pass the ...
- 199
0
votes
0
answers
51
views
Java Array behaving as call-by-reference only sometimes [duplicate]
I've encountered an interesting issue in Java - I don't know if it's a well known thing (I don't even know what to search for!).
Code:
public static void main(String[] args) {
String[] fruits = {&...
- 75
5
votes
1
answer
112
views
Difference on passing a free function as template argument by value or by reference
Consider this code (godbolt):
#include <iostream>
template<typename F> void call_by_val(F funct)
{
std::cout << "call_by_val(): ";
funct();
}
template<...
- 796
-3
votes
1
answer
95
views
Understanding when a compiler copies, moves or constructs in place [closed]
I've been reading up on copy and move semantics to improve my knowledge of when to use T vs T const & vs T &&
I wrote a small bit of test code to verify my intuition
#include <iostream&...
- 683
1
vote
2
answers
144
views
Updating a Java Map by different methods
I have a Java Map:
Map<String,String> mapThings = new HashMap<>();
updateMapThings(mapThings, sourceMap); // sourceMap is the original Map which has all the
...
- 978
0
votes
0
answers
46
views
If I have a HashMap<String, List<String>> and I want to update a List<String> value, why do I need to put the updated list back into the map? [duplicate]
If I have a Map<String, List<String>> and I want to get the List<String> value for a given key, and then append something to that list, why do I need to call map.put(key, list) to ...
- 63
0
votes
2
answers
53
views
Dart pass by reference or pass by value [duplicate]
I am working on a Dart project and found it confusing about the value assignment for Dart. Before this, I did some research on google which it tells me that the value assignment for Dart is pass by ...
- 348
0
votes
0
answers
25
views
When passing a pointer to a function in c, what actually happens? [duplicate]
I am trying to learn linked lists. In this I need to use a double pointer to pass by reference. But I am wondering, when we pass a pointer to the function, aren't we sending a copy of the address to ...
