For quick look at your C or CPP files in VS Code can give you unintended error check as VS Code doesn’t know better. You just wanted to read the file. Not necessary work on it. So how to get rid of the underlined red errors?

Solution
VS Code has separate error check for each file type. But for C and CPP it’s fairy simple. Open the command palette
CTRL + SHIFT + P
Then search for error squiggles. Here you will be able to enabled and disable the error checking.

Disable error squiggles and you’ll see the result right away. You can now read your C and CPP files without red lines.