title: QT creator : error: symbol(s) not found for architecture x86_64
body: <p>I'm trying to run this simple code in QT Creator.</p>
  
  <pre><code>    #include&lt;iostream&gt;
      using namespace std;
  
      const int SENTINEL = 0;
      int main() {
          cout&lt;&lt;"This program adds a list of numbers "&lt;&lt;endl;
          cout&lt;&lt;"Use "&lt;&lt;SENTINEL&lt;&lt;" to signal the end."&lt;&lt;endl;
          int total = 0;
          while(true) {
              int value;
              cout&lt;&lt;" ? ";
              cin&gt;&gt;value;
              if(value == SENTINEL) break;
              total += value;
          }
          cout&lt;&lt;"The total is "&lt;&lt;total&lt;&lt;endl;
          return 0;
      }
  </code></pre>
  
  <p>But I keep on getting this two issues.</p>
  
  <ol>
  <li><p>error: symbol(s) not found for architecture x86_64</p></li>
  <li><p>error: linker command failed with exit code 1 (use -v to see invocation)</p></li>
  </ol>
  
  <p>And the full description that I get is this. Inside Compile Output.</p>
  
  <blockquote>
    <p>Undefined symbols for architecture x86_64:   "Main()", referenced
    from:
          Main(int, char**) in main.o ld: symbol(s) not found for architecture x86_64 clang: error: linker command failed with exit code
    1 (use -v to see invocation) make: ***
    [simple-project.app/Contents/MacOS/simple-project] Error 1 00:04:36:
    The process "/usr/bin/make" exited with code 2. Error while
    building/deploying project simple-project (kit: Desktop Qt 5.7.0 clang
    64bit) When executing step "Make" 00:04:36: Elapsed time: 00:27.</p>
  </blockquote>