捕获异常：除以零 [英] Catching exception: divide by zero

问题描述

下面的代码不捕获异常，当我尝试除以0.我需要抛出一个异常，或者计算机在运行时自动抛出一个异常？

$

  int i = 0; 
 
 cin>>一世; //如果有人输入零？ 
 
 try {
 i = 5 / i; 
} 
 catch（std :: logic_error e）{
 
 cerr<< e.what（）; 
} 
  

解决方案

并抛出异常。整数除以零在标准C ++中不是一个例外。

浮点除以零，但至少具有处理它的具体方法。

ISO标准中列出的例外情况如下：

  namespace std {
 class logic_error; 
 class domain_error; 
 class invalid_argument; 
 class length_error; 
 class out_of_range; 
 class runtime_error; 
 class range_error; 
 class overflow_error; 
 class underflow_error; 
} 
  

你会认为 overflow_error <$ c $> c> C ++ 11 ，虽然我不认为这从以前的迭代改变了）具体说明：

如果 / 或％的第二个操作数为零，则此行为未定义。

所以，它可以抛出那个（或任何其他）异常。它也可以格式化您的硬盘和笑嘲讽： - ）

---

如果你想实现这样的野兽，在以下程序中使用 intDivEx ：

  #include< iostream> 
 #include< stdexcept> 
 
 //整数除法，捕捉除以零。 
 
 inline int intDivEx（int numerator，int denominator）{
 if（denominator == 0）
 throw std :: overflow_error（Divide by zero exception）; 
 return numerator / denominator; 
} 
 
 int main（void）{
 int i = 42; 
 
 try {
 i = intDivEx（10，2）; 
} catch（std :: overflow_error e）{
 std :: cout< e.what（）<  - >; 
} 
 std :: cout<< i<< std :: endl; 
 
 try {
 i = intDivEx（10，0）; 
} catch（std :: overflow_error e）{
 std :: cout< e.what（）<  - >; 
} 
 std :: cout<< i<< std :: endl; 
 
 return 0; 
} 
  

此输出：

  5 
除以零异常 - > 5 
  

，你可以看到它抛出和捕获异常除以零的情况。 >

---

等效的％几乎完全相同：

  //整数余数，除以零。 
 
 inline int intModEx（int numerator，int denominator）{
 if（denominator == 0）
 throw std :: overflow_error（Divide by zero exception）; 
 return numerator％denominator; 
} 
  

The following code does not catch an exception, when I try to divide by 0. Do I need to throw an exception, or does the computer automatically throw one at runtime?

int i = 0;

cin >> i;  // what if someone enters zero?

try {
    i = 5/i;
}
catch (std::logic_error e) {

    cerr << e.what();
}

解决方案

You need to check it yourself and throw an exception. Integer divide by zero is not an exception in standard C++.

Neither is floating point divide by zero but at least that has specific means for dealing with it.

The exceptions listed in the ISO standard are:

namespace std {
    class logic_error;
        class domain_error;
        class invalid_argument;
        class length_error;
        class out_of_range;
    class runtime_error;
        class range_error;
        class overflow_error;
        class underflow_error;
}

and you would think that overflow_error would be ideal for indicating a divide by zero.

But section 5.6 (of C++11, though I don't think this has changed from the previous iteration) specifically states:

If the second operand of / or % is zero, the behavior is undefined.

So, it could throw that (or any other) exception. It could also format your hard disk and laugh derisively :-)

---

If you wanted to implement such a beast, you could use something like intDivEx in the following program:

#include <iostream>
#include <stdexcept>

// Integer division, catching divide by zero.

inline int intDivEx (int numerator, int denominator) {
    if (denominator == 0)
        throw std::overflow_error("Divide by zero exception");
    return numerator / denominator;
}

int main (void) {
    int i = 42;

    try {
        i = intDivEx (10, 2);
    } catch (std::overflow_error e) {
        std::cout << e.what() << " -> ";
    }
    std::cout << i << std::endl;

    try {
        i = intDivEx (10, 0);
    } catch (std::overflow_error e) {
        std::cout << e.what() << " -> ";
    }
    std::cout << i << std::endl;

    return 0;
}

This outputs:

5
Divide by zero exception -> 5

and you can see it throws and catches the exception for the divide by zero case.

---

The % equivalent is almost exactly the same:

// Integer remainder, catching divide by zero.

inline int intModEx (int numerator, int denominator) {
    if (denominator == 0)
        throw std::overflow_error("Divide by zero exception");
    return numerator % denominator;
}

这篇关于捕获异常：除以零的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！