C++ Deque::operator!=() Function

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The C++ std::deque::operator!=() function is used to compare two deque for inequality. It returns true if the deque differ in size or if any corresponding elements are not equal otherwise it returns false. This operator is particularly useful for checking if two deques differ in content.

Syntax

Following is the syntax for std::deque::operator!=() function.

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

Parameters

• lhs, rhs − It indicates the deque container.

Return value

It returns true if the condition holds, otherwise false.

Exceptions

This function never throws exception.

Time complexity

The time complexity of this function is Linear i.e. O(n)

Example

In the following example, we are going to consider the basic usage of the operator!=() function.

#include <iostream>
#include <deque>
int main()
{
    std::deque<char> a = {'A', 'B', 'C'};
    std::deque<char> b = {'A', 'B', 'C'};
    if (a != b) {
        std::cout << "deques are not equal." << std::endl;
    } else {
        std::cout << "deques are equal." << std::endl;
    }
    return 0;
}

Output

Output of the above code is as follows −

deques are equal.

Example

Consider the following example, where we are going to compare the deques of different size.

#include <iostream>
#include <deque>
int main()
{
    std::deque<char> a = {'A', 'B', 'C'};
    std::deque<char> b = {'A', 'B'};
    if (a != b) {
        std::cout << "deques are not equal." << std::endl;
    } else {
        std::cout << "deques are equal." << std::endl;
    }
    return 0;
}

Output

Following is the output of the above code −

deques are not equal.

Example

In the following example, we are going to compare the deques of different elements.

#include <iostream>
#include <deque>
int main()
{
    std::deque<int> a = {10,12,23,34};
    std::deque<int> b = {01,12,23,34};
    if (a != b) {
        std::cout << "deques are not equal." << std::endl;
    } else {
        std::cout << "deques are equal." << std::endl;
    }
    return 0;
}

Output

If we run the above code it will generate the following output −

deques are not equal.