title: Add an element at the beginning of an array and shift the rest but keep the size
body: <p>I need to create a vector/array in the following format:</p>
  
  <pre><code>arr[10] = [1, 2, 3, 4, 5, 6, 7, 8, 9 ,10]
  </code></pre>
  
  <p>I want to add a new element at the beginning after which all elements are shifted to the right and the last element is deleted. The result should be:</p>
  
  <pre><code>arr[10] = [new_int, 1, 2, 3, 4, 5, 6, 7, 8, 9]
  </code></pre>
  
  <p>How can I do this in c++? Do I have to write a function or there is already an existing one like .append or .pushback?</p>