What is the unordered_map::find() function in C++?

In this shot, we will learn how to use the unordered_map::find() function.

Introduction

The unordered_map::find() function is available in the <unordered_map> header file in C++.

The unordered_map::find() searches a specific key in the unordered map.

Syntax

The syntax of the unordered_map::find() function is given below:

Iterator find(K key);

Parameter

The unordered_map::find() method accepts the parameter mentioned below:

Key: The key to be searched for in the unordered map.

Return value

The unordered_map::find() returns one of the two values:

Iterator: An iterator to the element when the key exists in the unordered map.
Iterator: An iterator to the end of the map when the key does not exist in the unordered map.

Code

Let us have a look at the code now:

#include <iostream>
#include <unordered_map>
using namespace std;
int main()
{
  unordered_map<int,int> umap ={
                        {12, 32},
                        {16, 899},
                        {89, 90},
                        {66, 46}
                      };
  if(umap.find(51) == umap.end())
    cout<<"The element with key = 51 is not present." << endl;
  else
    cout<<"The element with key = 51 is present."<<endl;
  
  if(umap.find(89) == umap.end())
    cout<<"The element with key = 89 is not present." << endl;
  else
    cout<<"The element with key = 89 is present." << endl;
  return 0;
}

Explanation

In lines 1 and 2, we import the required header files.
In line 5, we make a main() function.
From lines 7 to 12, we initialize an unordered_map with integer type keys and string type values.
From lines 14 to 17, we used an if-else statement to check whether the element with the specified key is present or not using the unordered_map::find() function. Here, we observe that the key is not present, and the corresponding message is printed.
From lines 19 to 22, we use an if-else statement again to check whether the element with the specified key is present or not using the unordered_map::find() function. This time, the key is present in the unordered map, and the corresponding message is printed.

This is how we use the unordered_map::find() function in C++.

Free AI Mock Interviews

Coding Interview

Coding PatternsFree Interview

Gain insights and practical experience with coding patterns through targeted MCQs and coding problems, designed to match and challenge your expertise level.

System Design

You TubeFree Interview

Learn to design a video streaming platform like YouTube by tackling functional and non-functional requirements, core components, and high-level to detailed design challenges.

Free Resources

License: Creative Commons-Attribution-ShareAlike 4.0 (CC-BY-SA 4.0)