Question

How to use #define to create function factory in C

Answer 1

#include <stdio.h>
 
// create function factory
#define FUNCTION(name, n) int fun_##name(int x) { return n * x;}
 
FUNCTION(f1, 3)
FUNCTION(f2, 4)
 

int main(void)
{
    printf("f1(15): %d\n", fun_f1(15) );
    printf("f2(17): %d\n", fun_f2(17) );
    
    return 0;
}

 
/*
run:

f1(15): 45
f2(17): 68

*/

 

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