C++ <deque> - operator!= Function

The C++ <deque> operator!= function is used to check whether two deques are unequal or not. It returns true if two deques are not 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

Return Value

Returns true if the contents of lhs are not 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 unequal 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 not equal.\n";
  else
    cout<<"dq1 and dq2 are equal.\n";

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

The output of the above code will be:

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