Check number of zeros elements 1D vector in C++

Question

I am using 1D vector in C++ such as

std::vector<int> A;

Have any way to check or count the number of zeros element in A using C++. For example

   A[0]=3;
   A[1]=0;
   A[2]=2;
   A[3]=0;

Then number of zeros element in A is 2.

Answer 1

A simple iteration over the vector, increasing the count everytime a zero element is encountered seems fine.

int count = 0;
for (int i = 0; i < A.size(); i++)
  {
    if (A[i] == 0)
      count++;
  }
return count;

You can also use the count function.

int ans = count(A.begin(), A.end(), 0);