c++ - 将字符数组用作多种用途的通用变量

Question

需要有关将 1 个字符数组用于多个用户输入的最佳方法的帮助，将用户输入数据传递给类 setMethod()，然后为下一个用户输入语句释放或重用相同的字符数组变量，冲洗并重复.我知道对于指针，您可以删除与它们关联的内存地址以释放空间，所以我认为这是我最好的选择？

// 9Application01.cpp
// Zachary James Mcclurg

#include "pch.h"
#include <iostream>
#include <string>
#include <sstream>

using namespace std;

const int NAME_SIZE = 20;
const int STREET_SIZE = 30;
const int CITY_SIZE = 20;
const int STATE_CODE_SIZE = 3;
const int MAXINPUT = 80;

class Customer
{
private:
long customerNumber;
char custName[NAME_SIZE];
char streetAddress_1[STREET_SIZE];


public:
bool setNum(long num);
bool setName(char namesize[]);
bool setAddress1(char address1[]);


long getNum() const;
char* getName();
char* getAdd1();
};


bool Customer::setNum(long num)
{
if (num > 99999 || num < 0) {
        cout << "Invalid input. Re-enter ";
        return false;
}
customerNumber = num;
return true;
}

bool Customer::setName(char namesize[MAXINPUT])
{
if (strlen(namesize) >= NAME_SIZE) {
    cout << "Invalid input. Re-enter ";
    return false;
}

strcpy_s(custName, namesize);
return true;
}

 bool Customer::setAddress1(char address1[MAXINPUT])
{
if (strlen(address1) >= NAME_SIZE) {
    cout << "Invalid input. Re-enter ";
    return false;
}

strcpy_s(streetAddress_1, address1);
return true;
}



// Getter Methods 

long Customer::getNum() const
{
return customerNumber;
}

char* Customer::getName()
{
return custName;
}

char* Customer::getAdd1()
{
return streetAddress_1;
}


int main()
{
Customer custom;

char dataLine[MAXINPUT];
long numLine;


cout << "Name: ";
cin.getline(dataLine, MAXINPUT);
custom.setName(dataLine);

cout << "Customer ID: ";
cin >> numLine;
custom.setNum(numLine);

cout << "Primary Address: ";
cin.getline(dataLine, MAXINPUT);
custom.setAddress1(dataLine);


cout << "Your Name is: " << custom.getName() << endl;
cout << "Your Customer ID is: " << custom.getNum() << endl;
cout << "Your Primary Address is: " << custom.getAdd1() << endl;

}

Answer 1

同一个字符数组可能被多次读取。只要不是动态分配就不需要清理:

#include <iostream>

int main()
{
  char cstr[50];
  while(std::cin.getline(cstr, 50))
  {
    std::cout << "I read \"" << cstr << "\"" << std::endl;
  }

  return 0;
}

如果数组是动态分配的(如果字符串大到足以导致堆栈溢出就应该是动态分配的)，您将不得不删除[]它一旦完成:

#include <iostream>

int main()
{
  auto cstr = new char[50];
  while(std::cin.getline(cstr, 50))
  {
    std::cout << "I read \"" << cstr << "\"" << std::endl;
  }

  delete[] cstr;
  return 0;
}

但是这段代码很危险。您可能会忘记清理或中间某处的异常可能会导致内存泄漏。您应该考虑 std::string 以获得最大的异常安全性，并且它也更易于使用。 std::string 通常保存一个指向堆上动态分配内存的指针，并且它还负责在字符串超出范围时清理它。这意味着您不必担心管理内存/堆栈溢出等问题。这是一个例子:

#include <iostream>
#include <string>

int main()
{
  auto line = std::string(); // guaranteed to make no copies with C++17
  while(std::getline(std::cin, line))
  {
    std::cout << "I read \"" << line << "\"" << std::endl;
  }

  // No need to clean up manually!
  return 0;
}