C++ <string> - clear() Function

The C++ string::clear function is used to clear all characters of the string. This function makes the string empty with a length of 0 characters.

Syntax

C++98
C++11

void clear();

void clear() noexcept;

Parameters

No parameter is required.

Return Value

None.

Time Complexity

Constant i.e, Θ(1)

Example:

In the example below, the string::clear function is used to clear all characters of the string called str.

#include <iostream>
#include <string>

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

  cout<<"Before clear() function: \n";
  cout<<"str contains: "<<str<<"\n";
  cout<<"str size: "<<str.size()<<"\n\n";

  str.clear();

  cout<<"After clear() function: \n";
  cout<<"str contains: "<<str<<"\n";
  cout<<"str size: "<<str.size();
  return 0;
}

The output of the above code will be:

Before clear() function: 
str contains: Hello World!.
str size: 13

After clear() function: 
str contains: 
str size: 0

❮ C++ <string> Library