negate function in C++ STL

Negate function is used to negate the given values such that to change the sign of the values. It changes the negative values to positive and vice-versa.

Function prototype:

function transform(a_begin, a_end, a1_begin, negate()):
   a_begin = lower bound of the array.
   a_end = upper bound of the array.
   a1_end = Lower bound of the second modified array.
   negate() = to negate the values of the array.

Example Code

#include <algorithm>
#include <functional>
#include <iostream>
using namespace std;
int main() {
   int a[] = { 4,6,7, -10, -20, -30 };
   transform(a, a + 6, a, negate<int>());
   for (int i = 0; i < 6; i++)
      cout << a[i] << ' ';
   return 0;
}

Output

-4 -6 -7 10 20 30