boost::algorithm::all_of() in C++ library
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; } |
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; } |
ALl elements are less than 7
Reference: https://www.boost.org/doc/libs/1_70_0/libs/algorithm/doc/html/algorithm/CXX11.html#the_boost_algorithm_library.CXX11.all_of
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