C++ Queue empty() Function

by Online Tutorials Library July 22, 2022

C++ Queue empty() Function

C++ Queue empty() function is used for testing whether the container is empty or not. Sometimes before actually starting the work with the individual elements of the containers, it is more feasible to look up if the container is empty, so this function finds its usage in such cases.

Syntax

Parameters

There are no parameters. The function is only used to test for the emptiness of the container and hence takes no parameter.

Return value

If the container under reference is empty, then the method returns ‘true’ else returns ‘false’.

Example 1

  #include <iostream>  #include <queue>  int main()  {  std::queue<int> newqueue;  int result=0;  for (int j=1; j<=10; j++)  newqueue.push(j);  while (!newqueue.empty () )  {  result += newqueue.front ();  newqueue.pop();  }  std::cout << “result is: ” << result;  return 0;  }  

Output:

result is: 55

Example 2

  #include <iostream>  #include <queue>  using namespace std;  int main()  {  queue<int> newqueue;  newqueue.push(55);  if(newqueue.empty())  {  cout<<“The queue is empty”;  }  else  {  cout<<“The queue is not empty”;  }  return 0;  }  

Output:

The queue is  not empty

Complexity

The complexity of the function is constant.

Data races

Only the container is accessed. By accessing the container, we come to know whether it is empty or not and based on that the value is returned.

Exception Safety

Guarantee as equivalent to the operations that are performed on the underlying container object is provided.

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C++ Queue empty() Function

C++ Queue empty() Function

Syntax

Parameters

Return value

Example 1

Example 2

Complexity

Data races

Exception Safety

What is boot

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