C++ <string> - empty() Function

The C++ string::empty function is used to check whether the string is empty or not. It returns true if the length of the string is zero, else returns false.

Syntax

C++98
C++11

bool empty() const;

bool empty() const noexcept;

Parameters

No parameter is required.

Return Value

true if the size of the string is zero, else returns false.

Time Complexity

Constant i.e, Θ(1)

Example:

In the example below, the string::empty function is used to check whether the string is empty or not.

#include <iostream>
#include <string>

using namespace std;
 
int main (){
  string str1 = "Hello World!.";
  string str2 = "";

  cout<<"String is: "<<str1<<"\n";
  cout<<"String length: "<<str1.length()<<"\n";
  cout<<"Is it empty?: "<<str1.empty()<<"\n\n";

  cout<<"String is: "<<str2<<"\n";
  cout<<"String length: "<<str2.length()<<"\n";
  cout<<"Is it empty?: "<<str2.empty();
  return 0;
}

The output of the above code will be:

String is: Hello World!.
String length: 13
Is it empty?: 0

String is: 
String length: 0
Is it empty?: 1

❮ C++ <string> Library