Question

How to use generic print function with macro in C

Answer 1

#include <stdio.h>

void print_int(int i) { printf("int: %d\n", i); }
void print_double(double d) { printf("double: %g\n", d); }
void print_string(char *s) { printf("string: %s\n", s); }
void print_default() { puts("unknown argument"); }

#define print(X) _Generic((X), \
            int: print_int, \
            double: print_double, \
            char *: print_string, \
            default: print_default)(X)

int main(void) 
{
    print(100);
    print(3.14);
    print("c c++");
    print(10000000000000000L);
    
    return 0;
}
    
/*
run:
 
int: 100
double: 3.14
string: c c++
unknown argument

*/

 

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