How to Understand this #define in C [duplicate]

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• C preprocessor # and ## operators 1 answer

I'm currently reading "The C puzzle book" and I found a #define that I would like to understand how it works.

#define PRINT(int) printf(#int " = %d\n", int)

I've never seen something like #int before so I wrote a small program to try the above

#include <stdio.h>
#define PRINT(int) printf(#int " = %d\n", int)
int main()
{
    PRINT(10);
}

Result: 10 = 10

How does the preprocessor interpret #int in this case and where can I read more about this?

Thanks.