C++ Forward_list Library - operator<= Function

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Description

The C++ function std::forward_list::operator<= tests whether first forward_list is less than or equal to other or not.

Declaration

Following is the declaration for std::forward_list::operator<= function form std::forward_list header.

C++11

template <class T, class Alloc>
bool operator<= (const forward_list<T,Alloc>& first, const forward_list<T,Alloc>& second);

Parameters

• first − First forward_list object.

• second − Second forward_list object of same type.

Return value

Returns true if first forward_list is less than or equal to second otherwise false.

Exceptions

This function never throws exception.

Time complexity

Linear i.e. O(n)

Example

The following example shows the usage of std::forward_list::operator<= function.

#include <iostream>
#include <forward_list>

using namespace std;

int main(void) {

   forward_list<int> fl1 = {1, 2, 3, 4, 5};
   forward_list<int> fl2 = {1, 2, 3, 4, 5};

   if (fl1 <= fl2)
      cout << "First list is less than or equal to second." << endl;

   fl1.push_front(6);

   if (!(fl1 <= fl2))
      cout << "First list is not less than or equal to second." << endl;

   return 0;
}

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

First list is less than or equal to second.
First list is not less than or equal to second.