title: Hundreds of build errors running code in Visual Studio
body: <p>Having this issue when I run my code and I get like 450 build errors when trying to run the code.</p>
  
  <p>This program is for a univerisy coursework so I was mainly working on it from my computer in my room but I went to uni to ask some questions, got my code from github, tried running and that's when I got all those erros. I asked the teacher and he said that's it probably because the windows or VS versions are different but all I had to do was right-click on the project and press "Retarget solution". It worked.</p>
  
  <p>But I'm back home and I did the retarget solution, but for some reason it doesn't seem to be doing anything and I'm getting all these errors.<a href="https://i.stack.imgur.com/Z1tMW.png" rel="nofollow noreferrer">Error list</a></p>
  
  <p>Here's a few of those errors copied if it helps having them in text. These aren't classes in my project. I assume they're c++ standard libraries or classes.</p>
  
  <pre><code>Severity    Code    Description Project File    Line    Suppression State
  Error (active)  E1696   cannot open source file "errno.h"   Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cerrno  7   
  Error (active)  E1696   cannot open source file "float.h"   Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cfloat  7   
  Error (active)  E1696   cannot open source file "corecrt.h" Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\crtdefs.h   10  
  Error (active)  E1696   cannot open source file "stddef.h"  Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cstddef 7   
  Error (active)  E1696   cannot open source file "stdio.h"   Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cstdio  8   
  Error (active)  E1696   cannot open source file "stdlib.h"  Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cstdlib 8   
  Error (active)  E1696   cannot open source file "math.h"    Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cstdlib 9   
  Error (active)  E0282   the global scope has no "acosf" Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   27  
  Error (active)  E0282   the global scope has no "acoshf"    Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   32  
  Error (active)  E0282   the global scope has no "asinf" Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   37  
  Error (active)  E0282   the global scope has no "asinhf"    Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   42  
  Error (active)  E0282   the global scope has no "atanf" Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   47  
  Error (active)  E0282   the global scope has no "atanhf"    Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   52  
  Error (active)  E0282   the global scope has no "atan2f"    Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   57  
  Error (active)  E0282   the global scope has no "cbrtf" Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   62  
  Error (active)  E0282   the global scope has no "ceilf" Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   67  
  Error (active)  E0282   the global scope has no "copysignf" Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   73  
  Error (active)  E0282   the global scope has no "cosf"  Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   78  
  Error (active)  E0282   the global scope has no "coshf" Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   83  
  Error (active)  E0282   the global scope has no "erff"  Coursework  C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\VC\Tools\MSVC\14.15.26726\include\cmath   88  
  </code></pre>