C++ <string> - length() Function

The C++ string::length function is used find out the total number of characters in a string. The function returns the number of actual bytes that conform the contents of the string, and it is not necessarily equal to its storage capacity.

Note: Both string::length and string::size functions are synonyms and return the same value.

Syntax

• C++98
• C++11

size_t length() const;

size_t length() const noexcept;

Parameters

No parameter is required.

Return Type

Number of characters present in the string.

Time Complexity

Constant i.e, Θ(1)

Example:

In the example below, the string::length function is used find out the total number of characters in the string called str.

#include <iostream>
#include <string>

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

  cout<<"The String is: "<<str<<"\n"; 
  cout<<"String length is: "<<str.length()<<"\n";
  cout<<"String size is: "<<str.size()<<"\n";
  return 0;
}

The output of the above code will be:

The String is: Hello World!.
String length is: 13
String size is: 13