我正在尝试测试以下异常处理代码:
#include "Array_Template.h"
using namespace std;
int main()
{
Array<int> intArr1;
//attempt to use out-of-range subscript
try{
cout << "\nAttempt to assign 1000 to intArr1[6]" << endl;
intArr1[6] = 1000;
} //end try
catch (const out_of_range &ex){
cout << "An exception occurred: " << ex.what() << endl;
} //end catch
return 0;
} //end main
在我的Array类模板中:
#ifndef ARRAY_H
#define ARRAY_H
#include <iostream>
#include <iomanip>
#include <cstdlib>
#include <stdexcept>
//forward declarations of friend functions as specializations of template
template<typename T> class Array;
template<typename T>
std::istream &operator>>(std::istream &, Array<T> &);
template<typename T>
std::ostream &operator<<(std::ostream &, const Array<T> &);
//Array class template
template<typename T>
class Array
{
friend std::istream &operator>> <>(std::istream &, Array<T> &);
friend std::ostream &operator<< <>(std::ostream &, const Array<T> &);
public:
Array(int = 5); //default constructor of array size 5
Array(const Array<T> &); //copy constructor
~Array(); //destructor
int getSize() const; //return size of array
const Array<T> &operator=(const Array<T> &); //overloaded assignment operator
bool operator==(const Array<T> &) const; //overloaded equality operator
bool operator!=(const Array<T> &r) const //overloaded inequality operator, inline definition
{
return !(*this == r); //invokes Array<T>::operator==
}
T &operator[](int); //overloaded subscript operator for non-const objects
T operator[](int) const; //overloaded subscript for const objects
private:
int size; //pointer-based array size
T *arrPtr; //pointer to first element of array
}; //end class Array
template<typename T>
Array<T>::Array(int s)
:size(s > 0 ? s : 5), arrPtr(new T[size])
{
for (int i = 0; i < size; ++i)
arrPtr[i] = 0;
} //end Array constructor
template<typename T>
//ref return creates a modifiable lvalue
T& Array<T>::operator[](int index)
{
if (index < 0 || index >= size) //check if out of bounds
throw std::out_of_range::out_of_range("index out of range");
return arrPtr[index]; //ref return
} //end operator[]
template<typename T>
//const ref return creates an rvalue
T Array<T>::operator[](int index) const
{
if (index < 0 || index >= size) //check if out of bounds
throw std::out_of_range::out_of_range("index out of range");
return arrPtr[index]; //returns copy of this element
} //end operator[]
#endif
程序在Visual Studio中编译并执行正常,显示正确的单行错误消息:
但是当我用gcc编译同一个程序并运行它时,我得到以下输出:
*`./arrays_template'出错:free():无效大小:0x0000000001426030 * ======= Backtrace:========= /lib64/libc.so.6(+0x7364f)[0x7fd7c2e3d64f] /lib64/libc.so.6(+0x78eae)[0x7fd7c2e42eae] /lib64/libc.so.6(+0x79b87)[0x7fd7c2e43b87] ./arrays_template [0x4011a1] ./arrays_template[0x400fc7] /lib64/libc.so.6(__libc_start_main+0xf5)[0x7fd7c2debbe5] ./arrays_template[0x400c29]
后面是一个冗长的内存映射跟踪。 有人可以解释这里到底发生了什么,以及如何解决它?通过修复我的意思是如何在catch块中指定打印相同的错误消息。
答案 0 :(得分:2)
下面的代码是错误的:
throw std::out_of_range::out_of_range("index out of range");
// ^^^^^^^^^^^^^^
应该重写为:
throw std::out_of_range("index out of range");
致电std::out_of_range
还要确保修改operator[](int) const
的返回类型。
答案 1 :(得分:2)
从
中更改两个运算符中的此语句throw std::out_of_range::out_of_range("index out of range");
到
throw std::out_of_range("index out of range");