Question

我试图重载加法运算符，但是我仍然遇到分段错误，即使我已经解除分配内存后按值传递参数。任何人都知道我可能做错了什么。另外，一旦我在修复重载加法后正确运行，我需要使用向量而不是指向数组，我不知道如何以与我对数组相同的方式声明。

RowAray.h

#ifndef ROWARAY_H // if constant ROWARAY_H not defined do not execute
#define ROWARAY_H // defines constant ROWARAY_H
#include <new>       // Needed for bad_alloc exception
#include <cstdlib>   // Needed for the exit function


template <class T>
class RowAray{
    private:
        int size;
        T *rowData;
        void memError();  // Handles memory allocation errors
        void subError();  // Handles subscripts out of range
    public:
        RowAray(T); //used to construct row Array object
        ~RowAray(){delete [] rowData;} //used to deallocate dynamically allocated memory from Row array
        int getSize(){return size;} //inline accessor member function used to return length of Row array
        void setData(int row, T value);
        T getData(int i){return (( i >=0&& i < size)?rowData[i]:0);} //
        T &operator[](const int &);
};
template <class T>
RowAray<T>::RowAray(T colSize){
     size =colSize>1?colSize:1; 
   // Allocate memory for the array.
   try
   {
      rowData = new T [size];
   }
   catch (bad_alloc)
   {
      memError();
   }

   // Initialize the array.
   for (int count = 0; count < size; count++){
       T value = rand()%90+10; 
        setData(count, value);
   }

}

template <class T>
void RowAray<T>::memError()
{
   cout << "ERROR:Cannot allocate memory.\n";
   exit(EXIT_FAILURE);
}

template <class T>
void RowAray<T>::subError()
{
   cout << "ERROR: Subscript out of range.\n";
   exit(EXIT_FAILURE);
}

template <class T>
T &RowAray<T>::operator[](const int &sub)
{
   if (sub < 0 || sub >= size)
      subError();
   else
       return rowData[sub];
}

template <class T>
void RowAray<T>::setData(int row, T value){
    //used to fill array with random 2 digit #s
      *(rowData + row) = value;
}

#endif  /* ROWARAY_H */

Table.h

#ifndef TABLE_H
#define TABLE_H

#include "RowAray.h"

template <class T>
class Table{
    private:
        int szRow;
        int szCol;
        RowAray<T> **records;

    public:
        Table(int,int); //used to construct Table object
        Table(const Table &);
        ~Table(); //used to deallocate dynamically allocated memory from Table object
        int getSzRow() const{return szRow;} //used to return row size
        int getSzCol()const {return szCol;}
        Table operator+(const Table &);
        T getRec(int, int) const; //used to return inserted random numbers of 2d arrays
};

template <class T>
Table<T>::Table(int r, int c ){
   //Set the row size
    this->szRow = r;
    //Declare the record array
    records = new RowAray<T>*[this->szRow];
    //Size each row
    this->szCol = c;
    //Create the record arrays
    for(int i=0;i<this->szRow;i++){
        records[i]=new RowAray<T>(this->szCol);
    }
}

template <class T>
Table<T>::Table(const Table &Tab){
    szRow=Tab.getSzRow();
    szCol=Tab.getSzCol();
    records = new RowAray<T>*[szCol];

    for(int i = 0; i < this->szCol; i++){
        records[i] = new RowAray<T>(szRow);
    }

    //set elements = to random value
    for(int row = 0; row < szRow; row++){
        for(int col = 0; col < this->szCol; col++){
            int value = Tab.getRec(row, col);
            records[col]->setData(row,value);
        }
    }


}

template <class T>
T Table<T>::getRec(int row, int col) const{
     //if else statement used to return randomly generated numbers of array
   if(row >= 0 && row < this->szRow && col >= 0 && col < this->szCol){
        return records[row]->getData(row);
    }else{
        return 0;
    }
}

template <class T>
Table<T>::~Table(){
    //Delete each record
    for(int i=0;i<this->szRow;i++){
        delete records[i];
    }
    delete []records;
}

template <class T>
Table<T> Table<T>::operator+(const Table &Tab){
    Table temp(Tab.getSzRow(), Tab.getSzCol());

    //set elements = to random value for operation to 
    for(int row=0; row < szRow; row++){
        for(int col=0; col < szCol; col++){
            int value = getRec(row, col) + Tab.getRec(row, col);
            temp.records[col]->setData(row,value);
        }
    }
    return temp;
}

#endif  /* TABLE_H */

的main.cpp

#include <cstdlib>
#include <ctime>
#include <iostream>
#include <iomanip>
using namespace std;

//User Libraries
#include "Table.h"

//Global Constants

//Function Prototype
template<class T>
void prntRow(T *,int);
template<class T>
void prntTab(const Table<T> &);

//Execution Begins Here!
int main(int argc, char** argv) {
   //Initialize the random seed
   srand(static_cast<unsigned int>(time(0)));

   //Declare Variables
   int rows=3,cols=4;

   //Test out the Row with integers and floats
   RowAray<int> a(3);
   RowAray<float> b(4);
   cout<<"Test the Integer Row "<<endl;
   prntRow(&a,3);
   cout<<"Test the Float Row "<<endl;
   prntRow(&b,4);

   //Test out the Table with a float
   Table<float> tab1(rows,cols);
   Table<float> tab2(tab1);
   Table<float> tab3 = tab1 + tab2;

   cout<<"Float Table 3 size is [row,col] = Table 1 + Table 2 ["
           <<rows<<","<<cols<<"]";
   prntTab(tab3);

   //Exit Stage Right
   return 0;
}

template<class T>
void prntRow(T *a,int perLine){
    cout<<fixed<<setprecision(1)<<showpoint<<endl;
    for(int i=0;i<a->getSize();i++){
        cout<<a->getData(i)<<" ";
        if(i%perLine==(perLine-1))cout<<endl;
    }
    cout<<endl;
}

template<class T>
void prntTab(const Table<T> &a){
    cout<<fixed<<setprecision(1)<<showpoint<<endl;
    for(int row=0;row<a.getSzRow();row++){
        for(int col=0;col<a.getSzCol();col++){
            cout<<setw(8)<<a.getRec(row,col);
        }
        cout<<endl;
    }
    cout<<endl;
}

Answer 1

你的错误来自Table.h的第85行，在你+运算符重载：

temp.records[col]->setData(row,value);

应该是

temp.records[row]->setData(col,value);

除此之外，我在第62行（方法Table<T>::getRec(int row, int col)）的同一文件中发现了另一个错误：

return records[row]->getData(row);

应该是

return records[row]->getData(col);

除了这些问题之外，我强烈建议您重新考虑并重新构建代码（也许您也可以尝试代码审查），因为我认为其中很大一部分是多余的，如果扩展，有些事情可能会成为问题项目（例如，RowAray的构造函数将T colSize作为参数，您应该使用int或更好的size_t。此代码因为当T不能隐式转换为整数类型时它不起作用。）

重载加法运算符和动态向量时的分段错误

1 个答案: