How to Check if a Map is Empty in C++ - Step by Step Examples

How to Check if a Map is Empty in C++ ?

Answer

To check if a map is empty in C++, you can use the empty method. This method returns a boolean value indicating whether the map contains any elements.

✐ Examples

1 Checking if a Map is Empty Using empty Method

We can check if a map is empty in C++ using the empty method, which returns true if the map contains no elements and false otherwise.

For example,

We start by including the <map> and <iostream> header files, which provide the necessary functions and data structures for working with maps and input-output operations.
We declare and initialize an empty map named myMap. In this example, the map has integer keys and string values.
We use the empty method to check if the map is empty. The empty method returns a boolean value indicating whether the map contains any elements.
We print the result to the console using std::cout.

C++ Program

#include <map>
#include <iostream>

int main() {
    // Declare and initialize an empty map
    std::map<int, std::string> myMap;

    // Check if the map is empty using empty method
    bool isEmpty = myMap.empty();

    // Print the result
    std::cout << "Is the map empty? " << (isEmpty ? "Yes" : "No") << std::endl;

    return 0;
}

Output

Is the map empty? Yes

2 Checking if a Non-Empty Map is Empty Using empty Method

We can check if a non-empty map is empty in C++ using the empty method, which returns false if the map contains elements.

For example,

We start by including the <map> and <iostream> header files, which provide the necessary functions and data structures for working with maps and input-output operations.
We declare and initialize a map named myMap with some key-value pairs. In this example, the map has integer keys and string values.
We use the empty method to check if the map is empty. The empty method returns a boolean value indicating whether the map contains any elements.
We print the result to the console using std::cout.

C++ Program

#include <map>
#include <iostream>

int main() {
    // Declare and initialize a map
    std::map<int, std::string> myMap = {
        {1, "one"},
        {2, "two"},
        {3, "three"}
    };

    // Check if the map is empty using empty method
    bool isEmpty = myMap.empty();

    // Print the result
    std::cout << "Is the map empty? " << (isEmpty ? "Yes" : "No") << std::endl;

    return 0;
}

Output

Is the map empty? No

3 Checking if a Map is Empty After Clearing Using empty Method

We can check if a map is empty in C++ after clearing its elements using the empty method, which returns true if the map contains no elements.

For example,

We start by including the <map> and <iostream> header files, which provide the necessary functions and data structures for working with maps and input-output operations.
We declare and initialize a map named myMap with some key-value pairs. In this example, the map has integer keys and string values.
We use the clear method to remove all elements from the map, making it empty.
We use the empty method to check if the map is empty after clearing. The empty method returns a boolean value indicating whether the map contains any elements.
We print the result to the console using std::cout.

C++ Program

#include <map>
#include <iostream>

int main() {
    // Declare and initialize a map
    std::map<int, std::string> myMap = {
        {1, "one"},
        {2, "two"},
        {3, "three"}
    };

    // Clear the map
    myMap.clear();

    // Check if the map is empty using empty method
    bool isEmpty = myMap.empty();

    // Print the result
    std::cout << "Is the map empty? " << (isEmpty ? "Yes" : "No") << std::endl;

    return 0;
}

Output

Is the map empty? Yes

Summary

In this tutorial, we learned How to Check if a Map is Empty in C++ language with well detailed examples.

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How to Check if a Map is Empty in C++ - Step by Step Examples