C++ <deque> - operator== Function

The C++ <deque> operator== function is used to check whether two deques are equal or not. It returns true if two deques are equal, else returns false. operator== compares elements of deques sequentially and stops comparison after first mismatch.

Syntax

C++98
C++11

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

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

Parameters

`lhs`	First deque.
`rhs`	Second deque.

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 example below, the operator== function is used to check whether two deques are equal or not.

#include <iostream>
#include <deque>
using namespace std;
 
int main (){
  deque<int> dq1 {10, 20, 30};
  deque<int> dq2 {10, 20, 30};
  deque<int> dq3 {10, 20};

  if (dq1 == dq2)
    cout<<"dq1 and dq2 are equal.\n";
  else
    cout<<"dq1 and dq2 are not equal.\n";

  if (dq1 == dq3)
    cout<<"dq1 and dq3 are equal.\n";
  else
    cout<<"dq1 and dq3 are not equal.\n";
    
  return 0;
}

The output of the above code will be:

dq1 and dq2 are equal.
dq1 and dq3 are not equal.

❮ C++ <deque> Library