How to use the count function in c++

The count() function in C can count the number of occurrences of a specific element in the container. The syntax is size_type count(const T& element) const; and returns the number of elements. If it does not exist, it returns 0.

Usage of count() function in C

in C The count() function is used to count the number of occurrences of a specific element in the container. It is a generic function that can be used for any container that implements the SequenceContainer interface, such as vector, list and array.

Syntax

<code class="cpp">size_type count(const T& element) const;</code>

Where:

• element: The element to be found.
• size_type: An unsigned integer representing the count returned by the function.

Return value

count() The function returns the number of elements in the container that match the given element. If there is no element in the container, 0 is returned.

Usage

To use the count() function, just specify a container and the element you want to find. For example:

<code class="cpp">#include <vector>

int main() {
  vector<int> myVector = {1, 2, 3, 4, 5};

  int count = myVector.count(3);

  cout << "The number of times 3 appears in the vector is: " << count << endl;

  return 0;
}</code>

Output:

<code>The number of times 3 appears in the vector is: 1</code>

Note

• count() function performs a linear search, so for For large containers, the time complexity may be higher.
• If you want to find the number of occurrences of multiple elements, you can use associative containers such as unordered_map or unordered_set, which are faster to find.

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