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

Last Updated : 30 May, 2019

The all_of_equal() function in C++ boost library is found under the header ‘boost/algorithm/cxx11/all_of.hpp’ which tests all the elements of a sequence against the value passed in the parameter and returns true if all the elements of the sequence are same. It takes a sequence and a value, and returns true if the all the elements are same in the sequence.

Syntax:

bool all_of_equal ( InputIterator first, InputIterator last, const &value)
or
bool all_of_equal ( const Range &R, const &value)

Parameters: The function accepts parameters as described below:

first: It specifies the input iterators to the initial positions in a sequence.
second: It specifies the input iterators to the final positions in a sequence.
value: It specifies a value which is to be checked against for all the elements of the sequence.
R: It is the complete sequence.

Return Value: The function returns true if all the elements of the sequence is equal to value, else it returns false.

Below is the implementation of the above approach:

Program-1:

// C++ program to implement the 
// above mentioned function 
  
#include <bits/stdc++.h> 
#include <boost/algorithm/cxx11/all_of.hpp> 
using namespace std; 
  
// Drivers code 
int main() 
{ 
  
    // Declares the sequence with 
    // 5 length and all elements as 1 
    // [1, 1, 1, 1, 1] 
    vector<int> c(5, 1); 
  
    // Run the function 
    bool ans 
        = boost::algorithm::all_of_equal(c, 1); 
  
    // Condition to check 
    if (ans == 1) 
        cout << "ALl elements are 1"; 
    else
        cout << "All elements are not 1"; 
    return 0; 
} 

Output:

ALl elements are 1

Program-2:

// C++ program to implement the 
// above mentioned function 
  
#include <bits/stdc++.h> 
#include <boost/algorithm/cxx11/all_of.hpp> 
using namespace std; 
  
// Drivers code 
int main() 
{ 
  
    // Declares the sequence 
    int a[] = { 1, 2, 5, 6 }; 
  
    // Run the function 
    bool ans 
        = boost::algorithm::all_of_equal(a, a + 4, 4); 
  
    // Condition to check 
    if (ans == 1) 
        cout << "ALl elements are 4"; 
    else
        cout << "All elements are not 4"; 
    return 0; 
} 