Questions tagged [range-based-loop]
66 questions
1
vote
1 answer
Range based for loop iteration on std::map need for explanation
The following code is running properly
#include
#include
roi_saumon
- 489
- 4
- 13
1
vote
5 answers
How to add a list to a string?
I am trying to add a list to a string.
int main() {
std::cout << "Hello, welcome to Jay's Coffee!!\n";
std::string name; std::cout <<"What is your name "; std::cin >> name;
std::cout <<"Hello " << name << ", thank you so much for coming in…
user18326065
1
vote
1 answer
Continue in range based for loop after exception
I have the following program that iterates through a directory and can catch exceptions:
#include
#include
#include
int main() {
const std::filesystem::path md("/");
try {
for(auto const& dir :…
Gary Fisher
- 79
- 7
1
vote
1 answer
Why is this working in a normal for loop but not a range based for loop?
void set_fee(Patron p, int fee)
{
for (Patron x : patrons)
{
if (p.get_name() == x.get_name()) x.set_fee(fee);
}
for (int i = 0; i < patrons.size(); i++)
{
if (patrons[i].get_name() == p.get_name())…
yaelreshet11
- 131
- 5
1
vote
1 answer
How to take inputs using "range based for loop"
The loop containing "cin" doesn't change the values. What is happening inside the loop? And how can I use this(range based loop) to take inputs?
INPUT:-
#include
using namespace std;
int main()
{
int arr[]={1,2,3,4,5};
//with…
Pranshu_Taneja
- 186
- 1
- 1
- 16
1
vote
1 answer
What is the difference between range based loop and stringstream while extracting characters from a string
consider a string like string s = "xyz123".
for(char ch : s)
cout<>ch)
cout<
hashmalkani
- 43
- 7
1
vote
7 answers
Problem using iterators with dynamically allocated array
I have a variable k of type int to set the length of a dynamically allocated int array:
int *Numbers = new int[k];
But because of this I cannot iterate over the array, I get an error:
"no matching begin function was found required for this…
undefined
- 11
- 4
1
vote
3 answers
Auto reference for vectors?
The following code will not alter the contents of i in the for loop:
class Solution {
public:
vector> combinationSum(vector& candidates, int target) {
if (target == 0) {return vector>{{}};}
else if…
bayesianpower
- 93
- 2
- 8
0
votes
2 answers
Usage of std::span with non-iterable type
I was trying out some C++20 when I stumbled upon a rather strange (at least to me) situation. I was expecting the following code to not work with one of my examples (I've specified the expected behavior with comments), but it did work, and I want to…
Emiliano Toledo
- 11
- 1
0
votes
0 answers
How to make "auto" type deduction compatible with range-based "for"?
I am learning to make the self-defined class compatible with the range-based 'for' loop.
Given the range class:
class range
{
private:
range_iterator m_begin;
range_iterator m_end;
public:
range()
:
m_begin(0),
…
Xie Qing
- 81
- 7
0
votes
1 answer
Printing 2D array with forEach in C++, but without using auto keyword
I have come across the solution to print the 2 D array using C++.
The ans was to use auto keyword:
for eg:
double nut_torques[4][5]; // this is my array with type double
for (auto& rows : nut_torques)
{
for (auto cols : rows)
{
…
Chinmay
- 11
- 2
0
votes
0 answers
Range based for loop in function as reference throws error (C++)
I just learned range based for loops in c++ and i'm trying to create a function that initializes a vector to all 0's; i did the following:
#include
// #include
// #include
using namespace std;
void…
midi
- 11
0
votes
1 answer
r-value lifetime issue (stack-use-after-scope): How to move std::initializer_list
Usage
I have two classes, which give me a counter in range based for loops (bit like a simple ranges v3 lib).
// Usage with l-values
std::initializer_list li = {10, 11, 12, 13, 14};
for (auto [value, index] : enumerate(li))
std::cout <<…
Marc
- 338
- 2
- 15
0
votes
1 answer
how to tell compiler to do "range based for loop" in string vector?
I have created a string vector and want to fill it with a "range-based for loop" but it doesn't work. What am I doing wrong?
invalid initialization of reference of type ‘int&’ from expression of type ‘std::__cxx11::basic_string’
Does the…
Fidelity
- 33
- 4
0
votes
0 answers
Difference between auto& and auto&& in structured binding used in range-based for loop
(Please let me know if this is a duplicate. I tried to search previous questions but couldn't find the same one.)
When structured binding is used in a range-based for loop like this:
for (auto & [k, v] : myMap) {...} or
for (auto && [k, v] : myMap)…
starriet
- 2,565
- 22
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