📜  C/C++ 中的#include 和Java的导入之间的区别

📅  最后修改于: 2021-09-14 02:34:57             🧑  作者: Mango

#include in C/C++ 在 C 语言的情况下, #include是程序中的一个标准或用户定义的文件,它告诉预处理器将另一个文件的内部内容插入到程序的源代码中。

句法:

方案一:
下面是一个 C 程序来演示#include的使用:

C
// C Program to demonstrate use of #include
#include 
  
// Header file loads all the
// necessary Input output
// file at beginning only
  
// Driver Code
int main()
{
    printf("GeeksforGeeks");
    return 0;
}


Java
// Java program to demonstrate use of import
import java.io.*;
  
// import statement doesn't load
// all the necessary files at
// beginning rather it loads
// only those files which it
// needs at the runtime
class GFG {
    public static void main(String[] args)
    {
        System.out.println("GeeksforGeeks");
    }
}


输出:

GeeksforGeeks

Javaimport 在Java, import语句用于加载整个包或包中的某些类。它写在类定义之前和包语句之后(如果存在)。

句法:

方案二:
下面是一个Java程序来演示import语句的使用:

Java

// Java program to demonstrate use of import
import java.io.*;
  
// import statement doesn't load
// all the necessary files at
// beginning rather it loads
// only those files which it
// needs at the runtime
class GFG {
    public static void main(String[] args)
    {
        System.out.println("GeeksforGeeks");
    }
}
输出:
GeeksforGeeks

C/C++ 中的 #includeJava的import都用于加载预定义的头文件或包,但存在一些差异,如下所示:

S No.                           #include in C/C++                                                                                          import in Java                                                   
1 It is mandatory to use the #include statement to include standard header files. Import statement in java is optional
2 It loads the file at the beginning only.        No class files will be loaded at the beginning. 
Whenever a particular class is used then only the corresponding class file will be loaded.
3 Unnecessary waste of memory and processor’s time. No such waste of memory and processor’s time.
4 Size of the program increases.      No increase in the size of the program.
5 It is also called as static include. It is also called as dynamic include.
想要从精选的视频和练习题中学习,请查看C++ 基础课程,从基础到高级 C++ 和C++ STL 课程,了解语言和 STL。要完成从学习语言到 DS Algo 等的准备工作,请参阅完整的面试准备课程