The C++ algorithm::any_of function is used to return true if pred returns true for any element in the range [first,last), else returns false. The function returns false for empty range.

### Syntax

```template <class InputIterator, class UnaryPredicate>
bool any_of (InputIterator first,
InputIterator last,
UnaryPredicate pred);
```

### Parameters

 `first` Specify initial position of the input iterator. The range used is [first,last). `last` Specify final position of the input iterator. The range used is [first,last). `pred` Specify an unary function that accepts an element in the range as argument, and returns a value convertible to bool. The function returns true if the element satisfy the given condition.

### Return Value

Returns true if pred returns true for any element in the range, else returns false. Returns false for empty range.

### Time Complexity

Up to Linear i.e, Θ(n).

### Example:

In the below example, the algorithm::any_of function is used to check whether any element of a given sequence satisfy the specified condition or not.

```#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;

bool isNegative (int i) {
return (i < 0) ;
}

int main (){
int arr[] = {10, 15, 12, -15, 14, -12};
vector<int> vec = {10, 15, 12, 15, 14, 12};

//check for negative element in the array
bool b1 = any_of(arr, arr+6, isNegative);

//check for negative element in the vector
bool b2 = any_of(vec.begin(), vec.end(), isNegative);

//print result for array
if(b1) {
cout<<"Array contains negative elements.\n";
}
else {
cout<<"Array does not contain negative element.\n";
}

//print result for vector
if(b2) {
cout<<"Vector contains negative elements.\n";
}
else {
cout<<"Vector does not contain negative element.\n";
}

return 0;
}
```

The output of the above code will be:

```Array contains negative elements.
Vector does not contain negative element.
```