std::string::empty() in C++

The std::string::empty() function in C++ is a predefined member function of the std::string class template. This function is used to check if a string is empty, i.e., whether its length is 0 or not, and returns a boolean value true if the string is empty otherwise, it returns false.

Syntax of String empty()

stringObj.empty();

Here, stringObj is the name of the string object.

Parameters of std::string::empty()

The std::string::empty() function does not take any parameters.

Return Value of string::empty()

The return value of the std::string::empty() tells us whether the string is empty or not.

• It returns true if the string length is 0, otherwise,
• It returns false.

Example of std::string::empty() in C++

Input: 
str1="GeeksforGeeks 
str2=""

Output: 
str1 is not empty
str2 is empty

The below example illustrates how we can use an empty() function to check if the given string is empty or not in C++.

// C++ code to demonstrate std::string::empty() to check for
// empty string
#include <iostream>
using namespace std;

int main()
{

    // declaring two strings
    string str1 = "GeeksforGeeks";
    string str2 = "";

    // checking if the given string is empty or not
    if (str1.empty()) {
        // string is found empty
        cout << "str1 is empty" << endl;
    }
    else {
        // string is not empty
        cout << "str1 is not empty" << endl;
    }

    if (str2.empty()) {
        cout << "str2 is empty" << endl;
    }
    else {
        cout << "str2 is not empty" << endl;
    }

    return 0;
}

str1 is not empty
str2 is empty

Time Complexity: O(1)
Auxilliary Space: O(1)

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Article Tags :

• C++ Programs
• C++
• STL
• cpp-string
• cpp-strings-library
• CPP Examples

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