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std::all_of() in C++

  • Difficulty Level : Medium
  • Last Updated : 06 Jul, 2017

The C++ function is defined in <algorithm> library in STL. This function operates on whole range of array elements and can save time to run a loop to check each elements one by one. It checks for a given property on every element and returns true when each element in range satisfies specified property, else returns false.

template <class InputIterator, class UnaryPredicate>
bool all_of (InputIterator first, InputIterator last, UnaryPredicate pred);
first : Input iterators to the initial positions in a sequence.
last : Input iterators to the final positions in a sequence.
pred : An unary predicate function that accepts an element and returns a bool.

Exception : Throws exception if either predicate or an operation on an iterator throws exception.

// C++ code to demonstrate working of all_of()
#include <vector>
#include <algorithm>
#include <iostream>
int main()
    std::vector<int> v(10, 2);
    // illustrate all_of
    if (std::all_of(v.cbegin(), v.cend(), [](int i){ return i % 2 == 0; })) 
        std::cout << "All numbers are even\n";


All numbers are even

// C++ code to demonstrate working of all_of()
#include<algorithm> // for all_of()
using namespace std;
int main()
    // Initializing array
    int ar[6] =  {1, 2, 3, 4, 5, -6};
    // Checking if all elements are positive
    all_of(ar, ar+6, [](int x) { return x>0; })?
          cout << "All are positive elements" :
          cout << "All are not positive elements";
    return 0;


All are not positive elements

In the above code, -6 being a negative element negates the condition and returns false.

Useful array algorithms STL functions

This article is contributed by Manjeet Singh . If you like GeeksforGeeks and would like to contribute, you can also write an article using or mail your article to See your article appearing on the GeeksforGeeks main page and help other Geeks.

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