C ++：如何让动态数组的索引由文件中的行确定 [英] C++: How to let the indexes of an dynamic array be determined by lines in a file

问题描述

我正在尝试制作三个动态数组，其索引取决于文本文件中的行数。然后我需要使其索引值可修改。我在想全球阵列是我最好的选择。

由于某些原因我不断收到以下编译器错误：
secondLab.obj：error LNK2019：未解析的外部符号void __cdecl arrayInput（...）

问题，我如何解决这个问题，基本符合我的程序的目标。

这是我的代码： / p>

  #include< iostream> 
 #include< fstream> 
 #include< iomanip> 
 #include< string> 
 #include< new> 
 
使用namespace std; 
 
 int INDEXES = 0; 
 
 string * names_Array = new string [INDEXES]; 
 double * rates_Array = new double [INDEXES]; 
 double * hours_Array = new double [INDEXES]; 
 
 void subscript （ifstream& int& string& double& double&）; 
 void arrayInput（istream& string []，double []，double []，
 string& double& ;）; 
 
 int main（）
 {
 string names; 
 double rates; 
 double hours; 
 
 string filename（employee sample file.txt）; 
 ifstream employeeInfo（filename.c_str（））; 
 
 if（employeeInfo.fail（））
 {
 cout<<< 对不起，文件没有成功打开。
<< 请确保您的文件存在，并且
< 重新运行程序。 << ENDL; 
} 
 
下标（employeeInfo，INDEXES，名称，费率，小时）; 
 
 arrayInput（employeeInfo，names_Array，rates_Array，hours_Array，
名称，费率，小时）; 
 
 cout<<< names_Array [0]<< endl 
<< names_Array [1]<< endl 
<< names_Array [2]<< endl 
<< names_Array [3]<< endl 
<< names_Array [4]<< ENDL; 
 
 delete [] names_Array; 
 delete [] rates_Array; 
 delete [] hours_Array; 
 
 system（pause）; 
 return 0; 
} 
 
 void下标（ifstream& employeeInfo，int& INDEXES，
 string& names，double& rates，double& hours）
 {
 while （！employeeInfo.eof（））
 {
 employeeInfo>>名称>>价格>>>小时; 
 
 INDEXES ++; 
} 
} 
 
 void arrayInput（ifstream& employeeInfo，string names_Array []，
 double rates_Array []，double hours_Array []，string& names，double&费率，双倍和小时）
 {
 int i = 0; 
 
 while（！employeeInfo.eof（））
 {
 employeeInfo>>名称>>价格>>>小时; 
 
 names_Array [i] = names; 
 rates_Array [i] = rate; 
 hours_Array [i] = hours; 
 
 i ++; 
} 
} 
  

解决方案

可以先计数行数，然后启动数组..并将数据填充到数组。

  subscript（employeeInfo ，INDEXES，姓名，费率，小时）; 
 names_Array = new string [INDEXES]; 
 rates_Array = new double [INDEXES]; 
 hours_Array = new double [INDEXES]; 
 arrayInput（employeeInfo，names_Array，rates_Array，hours_Array，names，rates，hours）; 
  

尝试这样..

I'm trying to make three dynamic arrays whose indexes are determined by the number of lines in a text file. I then need to make their index values modifiable. I was thinking that global arrays would be my best bet.

For some reason I keep receiving the following compiler error: secondLab.obj : error LNK2019: unresolved external symbol "void __cdecl arrayInput(...)

Question, how do I fix this and basically meet the goal of my program.

Here's my code:

#include <iostream>
#include <fstream>
#include <iomanip>
#include <string>
#include <new>

using namespace std;

int INDEXES = 0;

string *names_Array = new string[INDEXES];
double *rates_Array = new double[INDEXES];
double *hours_Array = new double[INDEXES];

void subscript(ifstream&, int&, string&, double&, double&);
void arrayInput(istream&, string [], double [], double[],
     string&, double&, double&);

int main ()
{
    string names;
    double rates;
    double hours;

    string filename("employee sample file.txt");
    ifstream employeeInfo(filename.c_str());

    if (employeeInfo.fail())
    {
        cout << "Sorry, file was not successfully opened. "
             << "Please make sure your file exists and\n" 
             << "re-run the program." << endl;
    }   

    subscript(employeeInfo, INDEXES, names, rates, hours);

    arrayInput(employeeInfo, names_Array, rates_Array, hours_Array,
    names, rates, hours);

    cout << names_Array[0] << endl
         << names_Array[1] << endl
         << names_Array[2] << endl
         << names_Array[3] << endl
         << names_Array[4] << endl;

    delete[] names_Array;
    delete[] rates_Array;
    delete[] hours_Array;

    system("pause");
    return 0;
}

void subscript(ifstream& employeeInfo, int& INDEXES,
    string& names, double& rates, double& hours)
{
    while(!employeeInfo.eof())
    {   
        employeeInfo >> names >> rates >> hours;

        INDEXES++;
    }
}

void arrayInput(ifstream& employeeInfo, string names_Array[], 
    double rates_Array[], double hours_Array[], string& names, double& rates, double& hours)
{
    int i = 0;

    while(!employeeInfo.eof())
    {
        employeeInfo >> names >> rates >> hours;

        names_Array[i] = names;
        rates_Array[i] = rates;
        hours_Array[i] = hours;

        i++;
    }
}

解决方案

u can count the numbers of lines at first .. then initiate the arrays .. and filling data to arrays..

 subscript(employeeInfo, INDEXES, names, rates, hours);
 names_Array = new string[INDEXES];
 rates_Array = new double[INDEXES];
 hours_Array = new double[INDEXES];
 arrayInput(employeeInfo, names_Array, rates_Array, hours_Array,names, rates, hours);

try like this ..

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