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MakeFile in C++ and its applications

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Given a C++ program and the task is to break the entire program in the form of Makefile. It is basically used to create .cpp file and .h file for each class/functions and its functionalities and later link them all through a Makefile command available in C++. Advantages:

  • It makes codes more concise and clear to read and debug.
  • No need to compile entire program every time whenever you make a change to a functionality or a class. Makefile will automatically compile only those files where change has occurred.
  • Generally, in long codes or projects, Makefile is widely used in order to present project in more systematic and efficient way.

Example: Create a program to find the factorial and multiplication of numbers and print it. Traditional Way 

CPP




// Program to calculate factorial and
// multiplication of two numbers.
#include<bits/stdc++.h>
using namespace std;
  
// Function to find factorial
int factorial(int n)
{
    if (n == 1)
        return 1;
    // Recursive Function to find 
    // factorial
    return n * factorial(n - 1);
}
  
// Function to multiply two numbers
int multiply(int a, int b)
{
    return a * b;
}
  
// Function to print
void print()
{
    cout << "makefile" << endl;
}
  
// Driver code
int main()
{
    int a = 1;
    int b = 2;
    cout << multiply(a, b) << endl;
    int fact = 5;
    cout << factorial(5) << endl;
    print();
    return 0;
}


Output:

2
120
makefile

Use Makefile to run the above program:

  • File Name: main.cpp 

CPP




#include <bits/stdc++.h>
  
// Note function.h which has all functions
// definitions has been included
#include "function.h"
  
using namespace std;
  
// Main program
int main()
{
    int num1 = 1;
    int num2 = 2;
    cout << multiply(num1, num2) << endl;
    int num3 = 5;
    cout << factorial(num3) << endl;
    print();
}


  • File Name: print.cpp 

CPP




#include <bits/stdc++.h>
  
// Definition of print function is
// present in function.h file
#include "function.h"
using namespace std;
  
void print()
{
    cout < "makefile" << endl;
}


  • File Name: factorial.cpp 

CPP




#include <bits/stdc++.h>
  
// Definition of factorial function
// is present in function.h file
#include "function.h"
using namespace std;
  
// Recursive factorial program
int factorial(int n)
{
    if (n == 1)
        return 1;
    return n * factorial(n - 1);
}


  • File Name: multiply.cpp 

CPP




#include <bits/stdc++.h>
  
// Definition of multiply function 
// is present in function.h file
#include "function.h"
using namespace std;
  
int multiply(int a, int b)
{
    return a * b;
}


  • File Name: function.h 

CPP




#ifndef FUNCTION_H
#define FUNCTION_H
  
void print();
int factorial(int);
int multiply(int, int);
  
#endif


Commands to Compile and Run above program:

Open Terminal and type commands:
g++ -c main.cpp
g++ -c print.cpp
g++ -c factorial.cpp
g++ -c multiply.cpp
g++ -o main.o print.o factorial.o multiply.o
./main

Note: g++ -c filename.cpp is used to create object file.

makefile



Last Updated : 12 Mar, 2024
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