title: void replaceLetters(char *text, char original, char new_char) should change text
body: <p>I've been tryring to solve this problem for hours now.</p>
  <pre><code>void replaceLetters(char *text, char original, char new_char) 
  {
    text = &quot;Randoi&quot;;
    for(int i = 0; i != '\0'; i++){
    if(text[i] == original){
    text[i] = new_char;
    }
  }
  </code></pre>
  <p>if I print out text in this function it's correct, but in the other function where this function is called the text doesn't change and i know there's something wrong with my pointers.</p>
  <p>Please give me a hint. Tanks a lot.</p>