Explain C code snippet: preprocessor + printf =?

Question

The output for this code snippet is %s is a string is a string. Please explain.

#include <stdio.h>

#define scanf "%s is a string"

int main()
{
    printf(scanf, scanf);  
}

Answer 1

What exactly do you want us to explain? Subsititute the macro and get

printf("%s is a string", "%s is a string");

The rest is the expected normal everyday behavior of printf.

P.S. #define scanf ...???