Question

继承头文件http://pastebin.com/g0z7LkeN 继承人实施文件http://pastebin.com/USHbjbYC

这是测试调试器文件（不应该更改它）

// FILE: sequence_test.cpp
// An interactive test program for the new sequence class
#include <cctype>       // Provides toupper
#include <iostream>     // Provides cout and cin
#include <cstdlib>      // Provides EXIT_SUCCESS
#include "sequence2.h"  // With value_type defined as double
using namespace std;
using namespace CISP430_A2;

// PROTOTYPES for functions used by this test program:
void print_menu( );
// Postcondition: A menu of choices for this program has been written to cout.

char get_user_command( );
// Postcondition: The user has been prompted to enter a one character command.
// The next character has been read (skipping blanks and newline characters), 
// and this character has been returned.

void show_sequence(sequence display);
// Postcondition: The items on display have been printed to cout (one per line).

double get_number( );
// Postcondition: The user has been prompted to enter a real number. The
// number has been read, echoed to the screen, and returned by the function.


int main( )
{
    sequence test; // A sequence that we’ll perform tests on
    char choice;   // A command character entered by the user

    cout << "I have initialized an empty sequence of real numbers." << endl;

    do
    {
        print_menu( );
        choice = toupper(get_user_command( ));
        switch (choice)
        {
            case '!': test.start( );
                      break;
            case '+': test.advance( );
                      break;
            case '?': if (test.is_item( ))
                          cout << "There is an item." << endl;
                      else 
                          cout << "There is no current item." << endl;
                      break;
            case 'C': if (test.is_item( ))
                           cout << "Current item is: " << test.current( ) << endl;
                      else
                          cout << "There is no current item." << endl;
                      break;
            case 'P': show_sequence(test);
                      break;
            case 'S': cout << "Size is " << test.size( ) << '.' << endl;
                      break;
            case 'I': test.insert(get_number( ));
                      break;
            case 'A': test.attach(get_number( ));
                      break;
            case 'R': test.remove_current( );
                      cout << "The current item has been removed." << endl;
                      break;     
            case 'Q': cout << "Ridicule is the best test of truth." << endl;
                      break;
            default:  cout << choice << " is invalid." << endl;
        }
    }
    while ((choice != 'Q'));

    return EXIT_SUCCESS;
}

void print_menu( )
// Library facilities used: iostream.h
{
    cout << endl; // Print blank line before the menu
    cout << "The following choices are available: " << endl;
    cout << " !   Activate the start( ) function" << endl;
    cout << " +   Activate the advance( ) function" << endl;
    cout << " ?   Print the result from the is_item( ) function" << endl;
    cout << " C   Print the result from the current( ) function" << endl;
    cout << " P   Print a copy of the entire sequence" << endl;
    cout << " S   Print the result from the size( ) function" << endl;
    cout << " I   Insert a new number with the insert(...) function" << endl;
    cout << " A   Attach a new number with the attach(...) function" << endl;
    cout << " R   Activate the remove_current( ) function" << endl;
    cout << " Q   Quit this test program" << endl;
}

char get_user_command( )
// Library facilities used: iostream
{
    char command;

    cout << "Enter choice: ";
    cin >> command; // Input of characters skips blanks and newline character

    return command;
}

void show_sequence(sequence display)
// Library facilities used: iostream
{
    for (display.start( ); display.is_item( ); display.advance( ))
        cout << display.current( ) << endl;
}

double get_number( )
// Library facilities used: iostream
{
    double result;

    cout << "Please enter a real number for the sequence: ";
    cin  >> result;
    cout << result << " has been read." << endl;
    return result;
}

当我点击debuger中的选项P来打印整个序列时，它永远无法正常工作并经常吐出垃圾，当我在调试或附加2个数字后在调试器菜单中单击c时，它似乎也无法正常工作。我分析了我的算法，我不明白他们为什么不正常工作..

Answer 1

<强>要点：

您正在使用默认构造函数创建类序列的实例，该构造函数不会分配您存储数字的数组，这会在从菜单调用任何函数时导致错误的行为，因为它们依赖于数组要正确初始化。您需要做的是使用另一个构造函数创建测试实例，即采用大小参数的构造函数。

原始文字

从上面的“测试调试器文件”看，我注意到你调用了类序列的默认构造函数：

sequence test; // A sequence that we’ll perform tests on

看看实现，我发现已经实现了它。我认为构造函数：

sequence(size_type entry=CAPACITY )

是您需要调用以“新”基础数组数据并在启动时正确设置索引的内容。例如，当前代码将从未初始化的随机存储器调用show_sequence（test）读取数据。

为什么我的打印功能吐出垃圾而我当前的功能无法正常工作？

1 个答案: