📜  C / C++中的#include和Java的import之间的区别

📅  最后修改于: 2021-05-30 20:15:55             🧑  作者: Mango

C / C++中的#include 对于C语言, #include是程序中的标准文件或用户定义文件,它告诉预处理器将另一个文件的内部内容插入程序的源代码中。

句法:

程序1:
下面是一个C程序,演示#include的用法:

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

用Java导入在Java, import语句用于加载整个包或包中的某些类。它是在类定义之前和package语句(如果存在)之后编写的。

句法:

程式2:
下面是一个Java程序,演示了import语句的用法:

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程序包,但下面列出了某些区别:

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.
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