files in the folder:

ls -l
-rw-r--r-- 1 ysgc staff 98 Aug 15 13:40 func1.cpp
-rw-r--r-- 1 ysgc staff 106 Aug 15 13:30 func2.cpp
-rw-r--r-- 1 ysgc staff 41 Aug 15 12:45 funcs.h
-rw-r--r-- 1 ysgc staff 198 Aug 15 13:48 main.cpp

// main.cpp
#include <iostream>
#include "funcs.h"
int main(){
    std::cout << std::endl;
    print_hello();
    std::cout << std::endl;
    std::cout << "The factorial of 5 is " << factorial(5) << std::endl;
    return 0;
}

//funcs.h
void print_hello();
int factorial(int n);

// func1.cpp
#include "funcs.h"

int factorial(int n){
    if (n != 1){
        return n*factorial(n-1);
    }
    return 1;
}

// func2.cpp
#include <iostream>
#include "funcs.h"

void print_hello(){
    std::cout << "hello world!!!" << std::endl;
}

1. Brute force

clang++ main.cpp func1.cpp func2.cpp -o hello && ./hello

hello world!!!

The factorial of 5 is 120

2. Makefile example 1

https://www.youtube.com/watch?v=aw9wHbFTnAQ

subl Makefile 注意这里M是大写的

all:
    clang++ main.cpp func1.cpp func2.cpp -o a.out
compile:
    

make && ./a.out 默认make第一个内容，这里是“all”

all:
    
compile:
    clang++ main.cpp func1.cpp func2.cpp -o a.out

make compile && ./a.out 指定需要运行的内容名字，这里是“compile”

all: main.o func1.o func2.o # has these dependencies
    clang++ main.o func1.o func2.o -o a.out && ./a.out

main.o: main.cpp # check if main.cpp exists or not
    clang++ -c main.cpp

func1.o: func1.cpp
    clang++ -c func1.cpp

func2.o: func2.cpp
    clang++ -c func2.cpp

clean:
    rm -rf *o a.out

# format
# target: dependency
#   command

make && make clean

# define variables
CC=clang++
CFLAGS=-c -Wall

all: main.cpp func1.o func2.o # has these dependencies
    $(CC) main.cpp func1.o func2.o -o a.out && ./a.out

func1.o: func1.cpp # check if func1.cpp exists or not
    $(CC) $(CFLAGS) func1.cpp

func2.o: func2.cpp
    $(CC) $(CFLAGS) func2.cpp

clean:
    rm -rf *o a.out

# format
# target: dependency
#   command

make && make clean

3. Makefile example 2

https://www.youtube.com/watch?v=_r7i5X0rXJk

// main.cpp
#include <cstdlib>
#include "message.h"

using namespace std;

int main(){
    message m;
    m.printMessage();

    return 0;
}

//message.h
#ifndef MESSAGE_H
#define MESSAGE_H

class message{
public:
    void printMessage();
};

#endif

//message.cpp
#include <iostream>
#include "message.h"
using namespace std;

void message::printMessage(){
    cout << "Makefile example\n";
}

#Makefile
all: main.cpp message.o
    clang++ main.cpp message.o -o a.out && ./a.out

message.o: message.cpp
    clang++ -c message.cpp

clean:
    rm -rf *o a.out

4. Example 3

https://www.youtube.com/watch?v=j02hcX7R1yI

• directly output an executable file
  • -o a.out, -o exe_file
• two steps:
  • link file: -c file1.cpp or -c file1.cpp -o file1.o
  • to exe: xxx.o yyy.o zzz.o -o exe_file