Xcode: fatal error: 'iostream' file not found

OS: macOS Big Sur Version 11.1
Xcode: Version 12.3

I haven’t run C++ on my Mac in 8 months or so. I am trying to run a simple helloworld.cpp file:

#include <iostream>
using namespace std;


int main() {
    std::cout << "Hello World!";

    return 0;
}

When I run cpp helloworld.cpp in my terminal I receive:

helloworld.cpp:1:10: fatal error: 'iostream' file not found

And when I run clang++ -v helloworld.cpp, it says (followed by a long error):

InstalledDir: /Library/Developer/CommandLineTools/usr/bin

I think the InstalledDir path is the problem based on other posts I’ve seen. When I run the code in Xcode or CLion it works fine. I looked at this tutorial on YouTube that changes the path to:

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/

However, I am confused as to how to change this path for the InstalledDir (assuming that’s the issue) so that it works in terminal, not just inside of Xcode.

Update: I also just tried using xcode-select --switch /Applications/Xcode.app/Contents/Developer/ to change the path from /Library/Developer/CommandLineTools/usr/bin and I am still receiving the error.

The error:

In file included from helloworld.cpp:1:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/iostream:37:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/ios:215:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__locale:14:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/string:504:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/string_view:175:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__string:57:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/algorithm:642:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/utility:204:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:144:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
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In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
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In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
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In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
In file included from /usr/local/include/stdint.h:59:
/usr/local/include/stdint.h:2:10: error: #include nested too deeply
#include <stddef.h>
         ^
/usr/local/include/stdint.h:72:11: error: #include nested too deeply
# include <sys/types.h>
          ^
/usr/local/include/stdint.h:76:10: error: #include nested too deeply
#include <limits.h>
         ^
/usr/local/include/stdint.h:82:11: error: #include nested too deeply
# include <inttypes.h>
          ^
In file included from helloworld.cpp:1:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/iostream:37:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/ios:215:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__locale:14:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/string:504:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/string_view:175:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__string:57:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/algorithm:642:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/utility:204:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:160:8: error: 
      no member named 'uint64_t' in the global namespace
using::uint64_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:162:8: error: 
      no member named 'int_least8_t' in the global namespace
using::int_least8_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:163:8: error: 
      no member named 'int_least16_t' in the global namespace
using::int_least16_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:164:8: error: 
      no member named 'int_least32_t' in the global namespace
using::int_least32_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:165:8: error: 
      no member named 'int_least64_t' in the global namespace
using::int_least64_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:167:8: error: 
      no member named 'uint_least8_t' in the global namespace
using::uint_least8_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:168:8: error: 
      no member named 'uint_least16_t' in the global namespace
using::uint_least16_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:169:8: error: 
      no member named 'uint_least32_t' in the global namespace
using::uint_least32_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:170:8: error: 
      no member named 'uint_least64_t' in the global namespace
using::uint_least64_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:172:8: error: 
      no member named 'int_fast8_t' in the global namespace
using::int_fast8_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:173:8: error: 
      no member named 'int_fast16_t' in the global namespace
using::int_fast16_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:174:8: error: 
      no member named 'int_fast32_t' in the global namespace
using::int_fast32_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:175:8: error: 
      no member named 'int_fast64_t' in the global namespace
using::int_fast64_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:177:8: error: 
      no member named 'uint_fast8_t' in the global namespace
using::uint_fast8_t;
     ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cstdint:178:8: error: 
      no member named 'uint_fast16_t' in the global namespace
using::uint_fast16_t;
     ~~^
fatal error: too many errors emitted, stopping now [-ferror-limit=]
20 errors generated.

This post has been solved in the comments.