domiyanyue

g++ main.o my_math.so -o a.out
# or 
g++ main.o -L. -lmy_math -o a.out

domiyanyue

g++ -shared -o libmy_math.so my_math.o

domiyanyue

g++ main.o -L. -lmy_math -o a.out

domiyanyue

g++ main.o libmy_math.a -o a.out

domiyanyue

ar cr libmy_math.a my_math.o

domiyanyue

g++ -c main.cpp -o main.o
g++ -c my_math.cpp -o my_math.o
g++ main.o my_math.o -o a.out
./a.out
0.5

domiyanyue

#include "my_math.h"
#include <iostream>

int main(){
    std::cout << reciprocal(2.0) << std::endl;
    return 0;
}

domiyanyue

#ifndef H_MY_MATH
#define H_MY_MATH

double reciprocal(double d);

#endif // H_MY_MATH

domiyanyue

#pragma once

struct Time {
    int hour;
    int minute;
};

void printTime(Time t);

domiyanyue

...
#ifndef TIME_H
#define TIME_H  
// replaced from first #include "time.h"
struct Time {
    int hour;
    int minute;
};
...
#endif