The unordered_map::max_size is a built in function in C++ STL. It returns maximum number of elements which unordered_map can hold. Maximum number of elements in any container depends upon system and library implementation.
Syntax
size unordered_map.max_size()
Parameters: It does not accept any parameters.
Return type: Unsigned integer a container can hold maximum elements.
Example 1
// C++ program to illustrate the // unordered_map::max_size function #include <bits/stdc++.h> using namespace std;
int main()
{ // declaration of unordered_map
unordered_map< int , int > sample;
cout << " Current size is : " << sample.size() << endl;
cout << " max size is : " << sample.max_size() << endl;
// insert elements
sample.insert({ 1, 10 });
sample.insert({ 2, 10 });
sample.insert({ 3, 10 });
sample.insert({ 4, 10 });
cout << " Current size is : " << sample.size() << endl;
cout << " max size is : " << sample.max_size() << endl;
return 0;
} |
Output:
Current size is : 0 max size is : 1152921504606846975 Current size is : 4 max size is : 1152921504606846975
Example 2
// C++ program to illustrate the // unordered_map::max_size function #include <bits/stdc++.h> using namespace std;
int main()
{ // declaration of unordered_map
unordered_map< char , int > sample;
cout << " Current size is : " << sample.size() << endl;
cout << " max size is : " << sample.max_size() << endl;
// insert elements
sample.insert({ 'a' , 10 });
sample.insert({ 'b' , 10 });
sample.insert({ 'c' , 10 });
cout << " Current size is : " << sample.size() << endl;
cout << " max size is : " << sample.max_size() << endl;
return 0;
} |
Output:
Current size is : 0 max size is : 1152921504606846975 Current size is : 3 max size is : 1152921504606846975
Complexity : Its complexity is constant.