C++ 和 Java 中捕获基类和派生类异常

2024年8月28日 | 阅读 4 分钟

在深入探讨我们的主题“在 C++ 和 Java 中将基类和派生类作为异常捕获”之前，让我们先了解什么是异常和异常处理。异常是我们在编程时发生的错误，通常被视为不必要的错误，或者更好地理解为。它们就像编程过程中遇到的障碍，而异常处理是用于处理发生的异常或限制的错误处理机制。

在 C++ 和 Java 编程语言中，有多种方法可以处理异常处理，并将基类和派生类作为异常的一部分进行捕获。

在基类和派生类被捕获为异常的情况下，我们必须在显示输出终端上看到，所声明的派生类的 catch 块出现在我们声明的基类类型之前。
上述说法是有效的，我们甚至可以重新检查，如果我们把基类放在派生类之前，那么我们声明的派生类将永远不会被访问到。

算法（在 C++ 和 Java 中将基类和派生类作为异常捕获）

示例

begin //code starts from here
   declare a class b.
   say another class d which inherits class b.
   now display an object of class d.
   Try: throw derived.
   Catch (d derived)
      Print "code has been caught in the derived exception".
   Catch (B b)
      Print "code has been caught in the base exception".
End

C++ 代码

//here, we are writing down the C++ programming language code to
//demonstrate the concept of Catching Base and 
//Derived Classes as Exceptions in both C++ and Java languages
#include <iostream>
using namespace std;
class base_ {
};
class derived_: public base_ {
};
int main()
{
	derived_ d;
	//these are some necessary functionalities we may use
	try {
		//this is the monitored code we use
		throw d;
	}
	catch (base_ b) {
		cout << "OH! Caught Based Exception occured";
	}
	catch (derived_ d) {
		//note: the catch block we wrote below will never get executed!
		cout << "oh! caught in the derived exception...";
	}
	getchar();
	return 0;
}

输出

prog.cpp: In function 'int main()':
prog.cpp:20:5: warning: exception of type 'derived_' will be caught
    catch (derived_ d) {
    ^
prog.cpp:17:5: warning:    by the earlier handler for 'base_.'
    catch (base_ b) {
/ tm  p /vLt kM  pH G zo.o
OH! Caught Based Exception occurred

C++ 代码

//here, we are writing down the C++ programming language code to
//demonstrate the concept of Catching Base and 
//Derived Classes as Exceptions in both C++ and Java languages
#include <iostream>
using namespace std;

class base_ {};
class derived : public base_ {};
int main()
{
	derived d;
    //these are some necessary functionalities we may use
	try {
	
		//this is the monitored code we use
		throw d;
	}
	catch (derived d) {
		cout << "the code has been caught in the derived exception";
	}
	catch (base_ b) {
		cout << "the code has been caught in the base exception";
	}
	//this below code snippet is to read out the next possible character
	getchar(); 
	return 0;
}

输出

/tmp /vL tk MpH  Gzo.o
the code has been caught in the derived exception

Java 代码

//here, we are writing down the Java programming language code to
//demonstrate the concept of Catching Base and 
//Derived Classes as Exceptions in both C++ and Java languages
class base_ extends Exception {
}
class derived_ extends base_ {
}
public class Main{
	public static void main(String args[])
	{
		try {
			throw new derived_();
		}
		catch (base_ b) {
		}
		catch (derived_ d) {
		}
	}
}

输出

/tmp /vL tk MpH  Gzo.o
./Main.java:13: error: exception Derived has already been caught
		catch (Derived d) {
		^
1 error

Java 代码

//here, we are writing down the Java programming language code to
//demonstrate the concept of Catching Base and 
//Derived Classes as Exceptions in both C++ and Java languages
class base_b extends Exception {}
class derived_d extends base_b {}
public class Main {
public static void main(String args[]) {
// below, we wrote the try block code snippet
try {
    //this is the monitored code we use
	throw new derived_d();
	}
	catch(base_b)	 {
	System.out.println("the code has been caught in the base exception");
	}
	catch(derived_d) {
	System.out.println("the code has been caught in the derived exception");
	}
}
}

输出

Main.java:12: error: exception Derived has already been caught
    catch(derived_d)  { System.out.println("the code has been caught in the derived exception");}

下一主题C++ 中 forward_list 的操作函数

C++ 和 Java 中捕获基类和派生类异常

算法（在 C++ 和 Java 中将基类和派生类作为异常捕获）

联系信息

关注我们

教程

面试题

在线编译器

Python

Java

.Net Framework

AI, ML and Data Science

Cloud Technology

B.Tech and MCA

Web Technology

PHP

Software Testing

Technical Interview

Java Interview

Python

Web Interview

Database Interview

B.Tech / MCA

Important Interview

Software Testing Interview

Company Interviews

Online Compilers

Multiple Choice Questions

C++ 教程

C++ 控制语句

C++ 函数

C++ 数组

C++ 类和对象

C++ 构造函数

C++ 继承

C++ 多态

C++ 抽象

C++ 命名空间

C++ 模板

C++ 字符串

C++ 指针

信号处理

C++ 异常

C++ 文件与流

C++ STL 教程

面试题

选择题

C++ 程序

C++ STL Stack

C++ STL Bitset

C++ STL Deque

C++ STL List

C++ STL Map

C++ STL Math

C++ STL priority_queue

C++ STL Queue

C++ STL Multiset

C++ STL Multimap

C++ STL Set

C++ STD Strings

C++ STL Vector

C++ 操纵符

C++ STL Algorithms

C++ Algorithm

C++ Iterators

C++ 杂项

C++ 和 Java 中捕获基类和派生类异常

算法（在 C++ 和 Java 中将基类和派生类作为异常捕获）

相关帖子

C++ 程序对 Valarray 元素执行数学运算

在 C/C++ 中打印字符串的所有子字符串，其中元音和辅音数量相等

C++ 复制省略

C++ Clamp

使用函数在 C++ 中添加两个数字

C++ 可折叠二叉树

std::swap 和 std::vector::swap 的区别

C++ 程序使用运算符重载连接两个字符串

C++ Std partition point

C++ 预处理器

订阅 Tpoint Tech

联系信息

关注我们

教程

面试题

在线编译器