简单Makefile

a.c

#include<stdio.h>
main(){
    out();
    in();
}

in.c

#include<stdio.h>
void in(){
    printf("This is in method!\n");
}

out.c

#include<stdio.h>
void out(){
    printf("This is out method!\n");
}

Makefile

edit:a.o in.o out.o
    cc -o edit a.o in.o out.o
a.o:a.c
    gcc -c a.c
in.o:in.c
    gcc -c in.c
out.o:out.c
    gcc -c out.c
clean:
    rm edit a.o in.o out.o