title: Insert white spaces into char array
body: <p>I have char array(vector) of chars and I want to insert white spaces in specific order.</p>
  
  <p>For example I have </p>
  
  <pre><code> ['A','B','C','D','E','F','G','H','J','K','L','M','N','O']
  </code></pre>
  
  <p>and vector with indexes of white spaces </p>
  
  <pre><code>[7 12] % white spaces should be add to 7 and 12 indexes (original string)
  </code></pre>
  
  <p>and want to have</p>
  
  <pre><code> ['A','B','C','D','E','F',' ','G','H','J','K', 'L', ' ','M','N','O']
  </code></pre>
  
  <p>Is there some build-in function? I started with nested loop to itarate the array and instert ' ', but it looks ugly.</p>