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× C++ Standard Library C++ STL Library


The C++ queue::operator== function is used to check whether two queues are equal or not. It returns true if two queues are equal, else returns false.

Syntax

template <class T, class Container>
bool operator== (const queue<T,Container>& lhs, const queue<T,Container>& rhs);
template <class T, class Container>
bool operator== (const queue<T,Container>& lhs, const queue<T,Container>& rhs);

Parameters

lhs First queue.
rhs Second queue.

Return Value

Returns true if the contents of lhs are equal to the contents of rhs, else returns false.

Time Complexity

Linear i.e, Θ(n).

Example:

In the below example, the queue::operator== function is used to check whether two queues are equal or not.

#include <iostream>
#include <queue>
using namespace std;
 
int main (){
  queue<int> q1;
  queue<int> q2;
  
  for(int i = 0; i<3; i++) {
    q1.push(i);
    q2.push(i);
  }

  if (q1 == q2)
    cout<<"q1 and q2 are equal.\n";
  else
    cout<<"q1 and q2 are not equal.\n";

  q1.pop();
  cout<<"\nAfter deleting first element of q1.\n";
  if (q1 == q2)
    cout<<"q1 and q2 are equal.\n";
  else
    cout<<"q1 and q2 are not equal.\n";
    
  return 0;
}

The output of the above code will be:

q1 and q2 are equal.

After deleting first element of q1.
q1 and q2 are not equal.

❮ C++ <queue> Library