title: Compilation Error in C++: undefined reference to `main' collect2: error: ld returned 1 exit status
body: <p>The command I'm running in Linux terminal is: </p>
  
  <pre><code>g++ -c main.cpp fraction.cpp ; g++ -WALL -o main.o fraction.o 
  </code></pre>
  
  <p>The full output of what is returned is: </p>
  
  <pre><code>/usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-   
  gnu/Scrt1.o: In function `_start':
  (.text+0x20): undefined reference to `main'
  collect2: error: ld returned 1 exit status
  </code></pre>
  
  <p>The <code>main.cpp</code> was written by my professor, and he is checking our fraction class against it, so the main shouldn't have an error.</p>