**Vectors** are useful data structures that act like dynamic one-dimensional arrays.

The **`clear()` function** is defined in the `<vector>` library. It is used to delete all the elements in a vector. When the vector is empty, its size becomes zero.

#    
## Parameters
This function takes no parameters.

#    
## Return value
The function returns nothing.

The changes are made directly to the vector.

#include <iostream>
#include <vector> // first include <vector>
using namespace std;

int main()
{
  //declaration of int vector
  vector<int> vec = {1, 2, 3, 4, 5};
  
  // returns length of vector as unsigned int
  unsigned int vecSize = vec.size();
  cout << "Before using clear(), size of vector: " << vecSize << endl;

  // calling clear()
  vec.clear();

  // recalculate size of vector
  vecSize = vec.size();
  cout << "After using clear(), size of vector: " << vecSize << endl;

  cout << endl;

  return 0;
}

What is std::vector::clear() in C++?

Deletes all elements in a vector, setting its size to zero. Returns nothing.

What is std::vector::clear() in C++?

Syntax

Parameters

Return value

Example