2D安全數組C++

Question

代碼正在編譯，但控制檯窗口消失。在print（）函數中是否有錯誤，或者是編譯器（Dev C++）？ 我嘗試以許多不同的方式在main（）函數中打印，但其中一些代碼在此代碼工作時給我提供了錯誤。

#include<iostream> 
#include<cstdlib> 
#include<cassert> 
using namespace std; 

const int ROW = 2; 
const int COL = 2; 

template<class T> class SA 
{ 
private: 
    int low, high; 
    T* p; 
public: 
    // default constructor 
    SA() 
    { 
     low = 0; 
     high = -1; 
     p = NULL; 
    } 
    // 2 parameter constructor lets us write 
    SA(int l, int h) 
    { 
     if ((h - l + 1) <= 0) 
     { 
      cout << "constructor error in bounds definition" << endl; 
      exit(1); 
     } 
     low = l; 
     high = h; 
     p = new T[h - l + 1]; 
    } 

    // single parameter constructor lets us 
    // SA x(10); and getting an array x indexed from 0 to 9 
    SA(int i) 
    { 
     low = 0; 
     high = i - 1; 
     p = new T[i]; 
    } 

    // copy constructor for pass by value and 
    // initialization 
    SA(const SA & s) 
    { 
     int size = s.high - s.low + 1; 
     p = new T[size]; 

     for (int i = 0; i < size; i++) 
      p[i] = s.p[i]; 
     low = s.low; 
     high = s.high; 
    } 

    // destructor 
    ~SA() 
    { 
     delete[] p; 
    } 

    //overloaded [] lets us write 
    //SA x(10,20); x[15]= 100; 
    T& operator[](int i) 
    { 
     if (i < low || i > high) 
     { 
      cout << "index " << i << " out of range" << endl; 
      exit(1); 
     } 
     return p[i - low]; 
    } 

    // overloaded assignment lets us assign one SA to another 
    SA & operator=(const SA & s) 
    { 
     if (this == &s) 
      return *this; 
     delete[] p; 
     int size = s.high - s.low + 1; 
     p = new T[size]; 

     for (int i = 0; i < size; i++) 
      p[i] = s.p[i]; 
     low = s.low; 
     high = s.high; 
     return *this; 
    } 
    // overloads << so we can directly print SAs 
    friend ostream& operator<<(ostream& os, SA s) 
    { 
     int size = s.high - s.low + 1; 
     for (int i = 0; i < size; i++) 
      cout << s.p[i] << endl; 
     return os; 
    }; 
    //end of ostream 
}; 
//end class of safeArray 

//Matrix class 
template<class T> class Matrix 
{ 
private: 

    SA<SA<T> > matrx; 
public: 
    //2 param for 2D array 
    Matrix(int r, int c) 
    { 
     matrx = SA<SA<T> >(0, r - 1); 
     for (int i = 0; i < r; i++) 
     { 
      matrx[i] = SA<T>(0, c - 1); 
     } 
    } 

    SA<T> operator[](int row) 
    { 
     return (matrx[row]); 
    } 

    void read() 
    { 
     for (int i = 0; i < ROW; i++) 
      for (int j = 0; j < COL; j++) 
       cin >> this->s[i][j]; 
    } 

    void print() 
    { 
     for (int i = 0; i < ROW; i++) 
      for (int j = 0; j < COL; j++) 
       cout << this->s[i][j] << "\t" << endl; 
    } 
}; 
//class Matrix 

int main() 
{ 

    Matrix<int> A(2, 2); 

    A[0][2] = 5; 
    cout << A[0][2]; 
    //A.print(); 
    /* 
    Matrix <int> A; 
    cout<<"Enter matrix A:"<<endl; 
    A.read(); 
    cout<<"Matrix A is: "<<endl; 
    A.print(); 
    */ 

    system("PAUSE"); 
    return 0; 
} 

Answer 1

你是試圖通過調用一個外部進程來暫停你的進程，那個調用失敗，順便說一句。你應該使用一個函數調用來暫停你自己的進程。

system("PAUSE"); // this is wrong. 
getch();   // this will wait for the user to press a key. 

您的矩陣A是2×2，其中一個索引超出範圍。

A[0][2] = 5; // out of bounds !! valid bounds are [0..(2-1 = 1)][0..1] 

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