boost::algorithm::equal() in C++ library

The equal() function in C++ boost library is found under the header ‘boost/algorithm/cxx11/equal.hpp’ tests to see if two sequences contain equal values. It returns a boolean value which determines if both the sequences are same or not.

Syntax:

bool equal ( InputIterator1 first1, InputIterator1 second1,
                  InputIterator2 first2, InputIterator2 second2 )
or 
bool equal ( InputIterator1 first1, InputIterator1 second1,
             InputIterator2 first2, InputIterator2 second2, 
             BinaryPredicate pred )

Parameters: The function accepts parameters as described below:

• first1: It specifies the input iterators to the initial positions in the first sequence.
• second1: It specifies the input iterators to the final positions in the first sequence.
• first2: It specifies the input iterators to the initial positions in the second sequence.
• second2: It specifies the input iterators to the final positions in the second sequence.
• p: It specifies the comparison predicate if specified.

Return Value: The function returns true if both the sequence are same, else it returns false.





Note: The above function runs for C++14 and above.

Program-1:

// C++ program to implement the
// above mentioned function

#include <bits/stdc++.h>
#include <boost/algorithm/cxx14/equal.hpp>
using namespace std;

// Drivers code
int main()
{

    // Declares the sequences
    int a[] = { 1, 2, 5, 6, 8 };

    int b[] = { 1, 2, 5, 6, 8 };

    // Run the function
    bool ans
        = boost::algorithm::equal(a, a + 5, b, b + 5);

    // Condition to check
    if (ans == 1)
        cout << "Sequence1 and Sequence2 are equal";
    else
        cout << "Sequence1 and Sequence2 are not equal";
    return 0;
}
Output:

Sequence1 and Sequence2 are equal

Program-2:

// C++ program to implement the
// above mentioned function

#include <bits/stdc++.h>
#include <boost/algorithm/cxx14/equal.hpp>
using namespace std;

// Drivers code
int main()
{

    // Declares the sequences
    int a[] = { 1, 2, 5, 6, 8 };

    int b[] = { 1, 2, 5 };

    // Run the function
    bool ans
        = boost::algorithm::equal(a, a + 5, b, b + 5);

    // Condition to check
    if (ans == 1)
        cout << "Sequence1 and Sequence2 are equal";
    else
        cout << "Sequence1 and Sequence2 are not equal";
    return 0;
}
Output:

Sequence1 and Sequence2 are not equal

Reference: https://www.boost.org/doc/libs/1_70_0/libs/algorithm/doc/html/algorithm/CXX14.html#the_boost_algorithm_library.CXX14.equal