warning：ignoring return value of "scanf",declared with attribute

"warn_unused_result"

This warning is issued by the compiler when the return value of the "scanf" function is ignored in your code. The "scanf" function is used to read input from the console or a file and store it in variables. It returns the number of input items successfully matched and assigned. Ignoring the return value can lead to unexpected behavior or errors in your program.

To fix this warning, you should always check the return value of "scanf" and handle any errors or unexpected input appropriately. You can also disable this warning by adding the following compiler flag to your code:

-Wno-unused-result