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

Last Updated : 30 May, 2019

The all_of() function in C++ boost library is found under the header ‘boost/algorithm/cxx11/all_of.hpp’ which tests all the elements of a sequence and returns true if they all share a property. It takes a sequence and a predicate, and returns true if the predicate returns true when applied to every element in the sequence.

Syntax:

bool all_of ( InputIterator first, InputIterator last, Predicate p )
or
bool all_of ( const Range &R, Predicate p)

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.
p: It specifies a unary predicate function that accepts an element and returns a bool.
R: It is the complete sequence.

Return Value: The function returns true if the given predicate is true on all the elements of the sequence, 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> 
  
// using boost::algorithm; 
#include <boost/algorithm/cxx11/all_of.hpp> 
  
using namespace std; 
  
// Predicate function to check if 
// the element is odd or not 
bool isOdd(int i) 
{ 
    return i % 2 == 1; 
} 
  
// 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 with the second syntax 
    bool ans 
        = boost::algorithm::all_of(c, isOdd); 
  
    // Condition to check 
    if (ans == 1) 
        cout << "ALl elements are odd"; 
    else
        cout << "All elements are even"; 
    return 0; 
} 

Output:

ALl elements are odd

Program-2:

// C++ program to implement the 
// above mentioned function 
  
#include <bits/stdc++.h> 
#include <boost/algorithm/cxx11/all_of.hpp> 
using namespace std; 
  
// using boost::algorithm; 
  
// Predicate function to check if 
// the elements are less than 7 or not 
bool allLessThanSeven(int i) 
{ 
    return i < 7; 
} 
  
// Drivers code 
int main() 
{ 
  
    // Declares the sequence 
    int a[] = { 1, 2, 5, 6 }; 
  
    // Run the function with the first syntax 
    bool ans 
        = boost::algorithm::all_of(a, 
                                   a + 4, 
                                   allLessThanSeven); 
  
    // Condition to check 
    if (ans == 1) 
        cout << "ALl elements are less than 7"; 
    else
        cout << "All elements are not less than 7"; 
    return 0; 
} 