Home - News ( United States | United Kingdom | Italy | Germany ) - Football scores

Showing content from https://www.tutorialspoint.com/cpp_standard_library/cpp_unordered_set_clear.htm below:

C++ Unordered Set Clear Function

The C++ std::unordered_set::clear() function is used to erase all the elements from the unordered_set container. This function doesn't make any changes if the current unordered_set is empty otherwise, it will erase all the elements from the unordered_set. when this function is invoked the size() function return a zero. The return type of this function is void, which implies that it does not return any value.

Following is the syntax of the C++ std::unordered_set::clear() function −

void clear();

• It does not accept any parameter.

This function does not return any value.

Let's look at the following example, where we are going to use the clear() function and observing the output.

#include<iostream>
#include<string>
#include<unordered_set>
using namespace std;

int main () {
   //create a unordered_set
   unordered_set<int> u_set = {1, 2, 3, 4, 5};
   cout<<"Contents of the u_set before the clear operation are: "<<endl;
   for(int n : u_set){
      cout<<n<<endl;
   }
   //using the clear() function
   u_set.clear();
   cout<<"Size of the u_set after the clear operation: "<<u_set.size();
}

If we run the above code it will generate the following output −

Contents of the u_set before the clear operation are: 
5
4
3
2
1
Size of the u_set after the clear operation: 0

Consider another scenario, where we are going to use the cler() function the unordered_set of type char.

#include<iostream>
#include<string>
#include<unordered_set>
using namespace std;

int main () {
   //create a unordered_set
   unordered_set<char> char_set = {'A', 'B', 'C', 'D', 'E'};
   cout<<"Contents of the char_set before the clear operation are: "<<endl;
   for(char c : char_set){
      cout<<c<<endl;
   }
   //using the clear() function
   char_set.clear();
   cout<<"Size of the char_set after the clear operation: "<<char_set.size();
}

Following is the output of the above code −

Contents of the char_set before the clear operation are: 
E
D
C
B
A
Size of the char_set after the clear operation: 0

Following is the another example of using the clear() function on the unordered_set of the type string.

#include<iostream>
#include<string>
#include<unordered_set>
using namespace std;

int main () {
   //create a unordered_set
   unordered_set<string> str_set = {"Rahul", "Mukesh", "Dinesh", "Raja"};
   cout<<"Contents of the str_set before the clear operation are: "<<endl;
   for(string s : str_set){
      cout<<s<<endl;
   }
   //using the clear() function
   str_set.clear();
   cout<<"Size of the str_set after the clear operation: "<<str_set.size();
}

Output of the above code is as follows −

Contents of the str_set before the clear operation are: 
Dinesh
Mukesh
Raja
Rahul
Size of the str_set after the clear operation: 0

RetroSearch is an open source project built by @garambo | Open a GitHub Issue

Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo

HTML: 3.2 | Encoding: UTF-8 | Version: 0.7.4