Question

在我的c ++中学习使用复制构造函数等我们得到了一个我们要完成的程序的模板，但是我的输出在我的输出流中抛出了时髦的asci字符。

继承我的主要课程：

#include <iostream>
using namespace std;
#include "Contact.h"
using namespace sict;

    int main(){
      Contact c("Empty Contact", 3);
      c.display();
      cout << "Enter Contact information: " << endl;
      c.read();
      c.display();
      cout << endl;
      for (int i = 0; i < 1000000; i++){
        Contact temp("Testing the contact with a looooong "
                     "name that should be taken care of", 20);
        if (!(i % 100000)){
          cout << i << ":" << endl;
          temp.display();
        }
      }
      return 0;
    }

Contact.cpp：

#include <cstring>
#include <iostream>
#include "Contact.h"
using namespace std;

namespace sict{


  void Contact::display()const{
    //display the name and go to new line
      cout<< _name << endl;
    // loop through elements of _pn up to _noPN and display them one by one
      for(int i = 0; i < _noPN ; i++){
      _pn[i].display();
      }
    // draw a 40 char line using '-' and go to new line
   cout<<"----------------------------------------"<<endl;


  }
    Contact::Contact(){
        _pn = nullptr;
    }
    Contact::Contact(const char* name, int number){
        strncpy(_name, name,40);
        _pn = new PhoneNumber[number];
        _noPN = number;

    }
    Contact::~Contact(){
         delete[] _pn;

    }


  void Contact::read(){
    cout << "Contact Name: ";
    cin.getline(_name, 41, '\n');
    cout << "Please enter " << _noPN << " phone numbers: " << endl;
    for (int i = 0; i < _noPN; i++){
      cout << i + 1 << ": ";
      _pn[i].read();
    }
  }



  bool Contact::isEmpty()const{
    return _pn == (PhoneNumber*)0;
  }
  void Contact::setEmpty(){
    _name[0] = 0;
    _noPN = 0;
    _pn = (PhoneNumber*)0;// same as _pn = nullptr;
  }
}

输出故障：

Empty Contact
----------------------------------------
Enter Contact information:
Contact Name: John Doe
Please enter 3 phone numbers:
1: Home, 123 1234567
2: Cell, 234 2345678
3: Work, 345 3456789
John Doe
Home..........., 123 123-4567
Cell..........., 234 234-5678
Work..........., 345 345-6789
----------------------------------------
    0:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------
    100000:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------
    200000:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------
    300000:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------
    400000:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------
    500000:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------
    600000:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------
    700000:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------
    800000:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------
    900000:
    Testing the contact with a looooong nameôoc·lÐ
    ----------------------------------------

看起来像是什么：

Empty Contact
----------------------------------------
Enter Contact information:
Contact Name: John Doe
Please enter 3 phone numbers:
1: Home, 123 1234567
2: Cell, 234 2345678
3: Work, 345 3456789
John Doe
Home..........., 123 123-4567
Cell..........., 234 234-5678
Work..........., 345 345-6789
----------------------------------------

0:
Testing the contact with a looooong name
----------------------------------------
100000:
Testing the contact with a looooong name
----------------------------------------
200000:
Testing the contact with a looooong name
----------------------------------------
300000:
Testing the contact with a looooong name
----------------------------------------
400000:
Testing the contact with a looooong name
----------------------------------------
500000:
Testing the contact with a looooong name
----------------------------------------
600000:
Testing the contact with a looooong name
----------------------------------------
700000:
Testing the contact with a looooong name
----------------------------------------
800000:
Testing the contact with a looooong name
----------------------------------------
900000:
Testing the contact with a looooong name
----------------------------------------

如您所见，在名称末尾添加了几个ascii字符

我可以添加程序的其余部分但是它很安静，如果请求我将编辑此帖并添加它们。

Answer 1

strncpy(_name, name,40);不会在字符串末尾添加空终止符。要解决此问题，只需添加一行_name[40] = '\0'即可。对于短字符串，它恰好复制它。对于较长的琴弦 - 它在第40个符号处停止。

来自cppreference

如果在复制整个数组src之前达到count，则生成的字符数组不会以空值终止。

C ++，Odd Asci输出我的程序

1 个答案: