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C++ Map and Multimap
Question 1
What will be the output of the following C++ program?
#include <bits/stdc++.h>
using namespace std;
int main()
{
multimap<int, int> mp;
mp.insert({ 2, 30 });
mp.insert({ 1, 40 });
mp.insert({ 3, 60 });
mp.insert({ 1, 20 });
mp.insert({ 5, 50 });
auto it = mp.equal_range(1);
for (auto itr = it.first; itr != it.second; ++itr) {
cout << itr->first
<< '\t' << itr->second << '\n';
}
return 0;
}
1 40
1 20
3 60
1 20
1 40
2 30
3 60
5 50
Question 2
What will be the output of the following C++ program?
#include <iostream>
#include <map>
using namespace std;
int main()
{
multimap<char, int> sample;
sample.insert(make_pair('a', 10));
sample.insert(make_pair('b', 20));
sample.insert(make_pair('b', 30));
sample.insert(make_pair('c', 40));
sample.insert(make_pair('c', 50));
cout << sample.rbegin()->first << " = " << sample.rbegin()->second;
}
c = 50
c = 40
b = 30
a = 10
Question 3
Can you use the [] operator to access elements in a std::multimap?
Yes, it returns a reference to the element with the given key
Yes, it returns a pointer to the element with the given key
No, it is not supported by std::multimap
It depends on the implementation of std::multimap
Question 4
How can you retrieve all the elements with a given key in a std::multimap?
By calling the find() function multiple times until it returns an invalid iterator
By calling the search() function with the key as an argument
By calling the equal_range() function with the key as an argument
By calling the get() function with the key as an argument
Question 5
What is the return type of the equal_range() function in a std::multimap?
A boolean value indicating whether the element was found
A reference to the element
A pointer to the element
A pair of iterators to the first and last element with the given key
Question 6
How is the std::map class implemented in C++?
As a linked list
As an array
As a red-black tree
As a hash table
Question 7
What is the output of the following code?
#include <iostream>
#include <map>
int main() {
std::map<int, int> m {{1, 2}, {3, 4}, {5, 6}};
m[3] = 5;
for (auto it = m.begin(); it != m.end(); ++it) {
std::cout << it->first << " " << it->second << std::endl;
}
return 0;
}
1 2
3 5
5 6
1 2
3 4
5 6
1 2
4 5
5 6
1 4
3 5
5 6
Question 8
Which of the following statements about the map container class in the STL is NOT true?
A map is an ordered container that stores only unique key value pairs.
A map is implemented as a linked list.
A map does not allow element modification or removal.
A map has constant time complexity for element access.
Question 9
What is the time complexity of clearing all elements from a map in the STL?
O(1)
O(n)
O(log n)
O(n log n)
Question 10
What is the time complexity of erasing an element from a map in the STL?
O(1)
O(n)
O(log n)
O(n log n)
There are 10 questions to complete.