【C99】#，##，#__VA_ARGS__，##__VA_ARGS__

#include <iostream>

#define LOG(para) printf("%d,%s\n",para,#para)

int main() {
    LOG(10);                
    return 0;
}

#include <iostream>

// #define LOG(para) printf("%d,%s\n",para,#para)
#define str(x) #x

int main() {
    char* s=str(10);
    std::cout<<s;         
    return 0;
}

#define MAKE_ID(a, b) a##b

int main() {
    int value123 = 42;
    int id = MAKE_ID(value, 123);
    return 0;
}

#define LOG(...) printf("Message: " #__VA_ARGS__)

int main() {
    LOG(Hello, world!);
    return 0;
}

#include <iostream>

#define LOG(level, ...) printf(level, ##__VA_ARGS__)

int main() {
    LOG("Hello, world!","aaa");
    LOG("a");           
    return 0;
}