A std::pair is an ordered, heterogeneous sequence of exactly two objects (it is a special case of std::tuple).
std::pair is a part of the C++ Standard Library, defined in the header <utility>.
Questions tagged [std-pair]
776 questions
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votes
1 answer
C++ error declaring std::pair inside template class
I want to avoid using the std::pair() constructor or std::make_pair() functions while inserting into a map. I also want to know the success status of the insert operation, so I cannot use operator[]. I tried the following code but it produces a…
Dinesh
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2 answers
Syntax to insert elements into multimap>>
My question is how to insert some element into multimap of the form
multimap>> someMap; //std skipped to simplify
I tried different syntaxes and i think the closest one may be this…
user3119781
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Strange memory leak while passing std::pair as argument
A constructor for my object:
Visited(/*...*/, unsigned d) : /*...*/, node(new Node(make_pair(d,this))) {}
Valgrind claims that:
==15806== 112 (56 direct, 56 indirect) bytes in 1 blocks are definitely lost in loss record 8 of 14
==15806== at…
pkubik
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2 answers
Push back to a static vector< pair > myVector;
I want to store an amount of information which will contain 1 string, and 9 doubles. This info will belong to one "item" so I want to sort by the name, and thus I have decided to put this into a vector of pairs, with the first section of the pair…
user3483187
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Identifier Unidentified in Default Constructor
I've been searching online a lot for how to fix this. Also tried making everything public, but I don't think that's the problem. Here's my header code:
#ifndef DEALER_HPP
#define DEALER_HPP
#include
class Dealer{
private:
…
ch-pub
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3 answers
How to provide a default value for the first of a pair?
I'm using a pair type:
typedef std::pair Nomnom;
Example places it's used:
void DoIt(const Nomnom &toNom) {
...
}
void DoItAgain(const Nomnom &toNomAgain) {
...
}
In my case it makes sense to offer a default value for…
Claudiu
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Accesing an element in vector of pair of integer and vector
In the following code, I receive segfault at the last line:
int MAX_ITER = 4, n = 5;
vector< pair > > InputVector(MAX_ITER);
srand((unsigned)time(NULL));
for (int i = 0; i < MAX_ITER; i++)
InputVector[i].second.resize(n);
for…
kamalbanga
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votes
1 answer
Reading pairs of doubles from file (C++)
For a clustering program I am writing, I need to read information from a file. I am trying to read coordinates from a file with a specific format:
1.90, 2
0.0, 4.01
6, 1.00
Unfortunately, I have not been able to do this, because of the newlines and…
Knaapje
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2 answers
How can I make a vector of pairs work like a hash table?
I'm working on a 1-bit bimodal branch prediction simulator for a class project. I was thinking of using an unordered_map for the table but I need to be able to set the size, so I was thinking using a vector of pairs and table.reserve(tableSize) may…
Riptyde4
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1 answer
Manipulating one of the values of a vector of pairs in C++
If I have a vector of doubles PMF I can divide all elements of the vector by a double count by using the transform command as follows:
transform(PMF.begin(),PMF.end(),PMF.begin(),bind2nd(divides(),count));
Now however, I have a vector of…
0
votes
1 answer
Detecting cyclic pairs
Assume a std::set< std::pair >, can somebody suggest an algorithm or approach to check whether there are cyclic pairs?
e.g.
std::set< std::pair > cyclic = { {'A', 'B'}, {'B', 'C'}, {'C', 'A'} };
std::set< std::pair
user2804578
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3 answers
Deallocating memory of object inside a pair of a vector
I would like to know how to de-allocate memory of an object inside a pair of a vector.
vector< pair > vectorObject;
I did try using an iterator to iterate through all the elements, but I am unsure of how to delete an object that is…
Todd
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2 answers
Get a value in a 2D Vector given a key
I have a 2D vector in which i want to use a character key to find a value. For example,
Here is my vector type:
vector>
characters: a b c d
double: 1.1 2.1 7.1 1.3
each double coorelates with a character value. I want search the…
user977154
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2 answers
Default specification of a C++ vector of pairs of strings as function parameter invalid on gcc-4.1.2?
This builds fine as a parameter to a function declaration on x64 VS100 (MSVC++ 2010) but fails on RHEL5 (gcc 4.1.2):
const std::vector >& = std::vector >()
The whole function…
squashed.bugaboo
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votes
3 answers
std::set containing pair with custom comparator
I have a vector < pair >, where double represents weight of a person and int represents the id of that person.
Now I need to convert it to set < pair < double, int > > to remove the duplicates based on the id of that person, but inside…
Jaydeep Solanki
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