c++ - 类中的while循环不会执行c++

Question

我有一个while循环作为类(class)的一部分。

#include <iostream>
#include <iomanip>
#include <fstream>

struct familyFinance{             //add 3rd member familyFinance;
  int acctNos; float Balance; struct familyFinance *nextNodePointer;
  struct familyFinance *dynMemory; 
};

using namespace std;
class myFinanceClass {
private:
string fileName="";
familyFinance *ptrHead = nullptr;
public:
  void setFileName(string){ fileName="Lab5Data.txt";}
void readFileAndBuildLinkedList(){
ifstream Lab3DataFileHandle;
 
 
familyFinance *ptrHead=nullptr;
//familyFinance *dynFinancePtr=nullptr;
 familyFinance *tempPtr;
 tempPtr=ptrHead;

  Lab3DataFileHandle.open(fileName.c_str());
  while (!Lab3DataFileHandle.eof( )) {
    familyFinance *dynFinancePtr= new familyFinance;


 Lab3DataFileHandle >> dynFinancePtr -> acctNos; 
 Lab3DataFileHandle >> dynFinancePtr -> Balance;
 
 //   familyFinance *nextNodePointer = nullptr;
  if (ptrHead == nullptr)  {
    ptrHead  = dynFinancePtr;
}

else {      
 tempPtr =  ptrHead;  


 while  (tempPtr -> nextNodePointer != nullptr )
    tempPtr = tempPtr->nextNodePointer;
      tempPtr->nextNodePointer = dynFinancePtr; 

   }

  }
  Lab3DataFileHandle.close();


}
void spitThemOut(){
  familyFinance *tempNodePtr;
  tempNodePtr = ptrHead;

这是While循环

  while (tempNodePtr) {


    cout << "Acct, Balance: " << setw(3)
         <<ptrHead->acctNos << " " <<ptrHead->Balance << endl;
 tempNodePtr = tempNodePtr->nextNodePointer;
  }
}

当我从main类中调用该函数时，我知道它可以读取该函数，只是不会执行while循环。我需要更改执行while循环。如果您在答案中举一个例子，那将是徒劳的。感谢您的时间。

Answer 1

如果while循环在方法中并在该类中定义，则该循环将不会执行，导致该语言不允许这样做。类中定义的方法不允许有任何循环。该类中定义的方法还有其他一些限制。可以通过在类中声明方法但在类外定义方法来解决这种情况，如下所示

class myFinanceClass {
    ...    // all the code before spitThemOut()
    void spitThemOut();
};

void myFinanceClass::spitThemOut() {
    ... // code to work
    while (tempNodePtr) {
        ...
    }
}