C++ Stack Library - operator!= Function

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Description

The C++ function std::stack::operator!= tests whether two stacks are equal or not.

Declaration

Following is the declaration for std::stack::operator!= function form std::stack header.

C++98

template <class T, class Container>
bool operator!= (const stack<T,Container>& stack1,
                 const stack<T,Container>& stack2);

Parameters

• stack1 − First stack.

• stack2 − Second stack.

Return value

Returns true if both stacks are unequal otherwise true.

Exceptions

This function never throws exception.

Time complexity

Linear i.e. O(n)

Example

The following example shows the usage of std::stack::operator!= function.

#include <iostream>
#include <stack>

using namespace std;

int main(void) {
   stack<int> s1;
   stack<int> s2;

   for (int i = 0; i < 5; ++i) {
      s1.push(i + 1);
      s2.push(i + 1);
   }

   s1.pop();

   if (s1 != s2)
      cout << "Both stacks not are equal." << endl;

   s1.push(5);

   if (!(s1 != s2))
      cout << "Both stacks are equal." << endl;

   return 0;
}

Let us compile and run the above program, this will produce the following result −

Both stacks not are equal.
Both stacks are equal.