在包含多个变量的自定义数据类型的矢量模板中访问变量 [英] Accessing variables in a template that is a vector of a custom data type with multiple variables

问题描述

如何在增量 itemtype 和 total c $ c>函数？我在下面的代码给我错误，如下所示：

Counter2.h：在成员函数'int Counter :: increment（T）'中：

Counter2.h：28：31：error：'itemtype'未在此范围内声明

Counter2.h：36：22：错误：'itemtype'未在此范围内声明

Counter2.h：36：39：错误：'total'未在此范围内声明

我必须能够使用命令计数器< T> counter; 其中T可以是任何类型，如字符串和 counter.increment（）

 ＃包括<串GT; 
 //＃include< cstdlib> 
＃include< vector> 
 
使用std :: vector; 
使用std :: string; 
 
模板< class T> 
类记录{
 public：
 T itemtype; 
 int total; 
}; 
 
模板< class T> 
 class Counter {
 vector<记录和LT; T> >数据; 
 public：
 int increment（T item）; 
 int count（T item）; 
 void printSummary（）; 
}; 
 
模板< class T> 
 int Counter< T> :: increment（T item）{
 bool check = false; 
 $ b $ for（int i = 0; i< data.size（itemtype）; i ++）{
 if（data [i] .itemtype == item）{
 data [I]。总++; 
 bool check = true; 
休息; 
 
 
 if（check == false）{
 data.push_back（itemtype = item，total = 1）; 
 
 
 
 int main（）{
 
计数器< string>计数器; 
 
 counter.increment（orange）; 
 counter.increment（orange）; 
 
返回0; 
 
  

解决方案

c> for（int i = 0; i< data.size（itemtype）; i ++）{

将会是： $ b

）和 0; i< data.size（）; i ++）{ > data.push_back（itemtype = item，total = 1）; 可以是：
$ b

1. data.push_back（{item，1}）; //通过使用初始化器列表; C ++ 11




2. 或者，
   
   

     Record r; 
    r.itemtype = item; 
    r.total = 1; 
    data.push_back（r）; 
     

你可以看看： http://www.cplusplus.com/reference/vector/vector/
知道关于std :: vector。

How do I access the variables itemtype and total within the increment function? The code I have below gives me errors as follows

Counter2.h: In member function ‘int Counter::increment(T)’:

Counter2.h:28:31: error: ‘itemtype’ was not declared in this scope

Counter2.h:36:22: error: ‘itemtype’ was not declared in this scope

Counter2.h:36:39: error: ‘total’ was not declared in this scope

I must be able to use the command Counter<T> counter; where T can be any type, such as string and counter.increment()

#include<string>
//#include<cstdlib>
#include<vector>

using std::vector;
using std::string;

template<class T>
class Record{
   public:
      T itemtype;
      int total;   
};

template<class T>
class Counter{
      vector< Record<T> > data;
   public:
      int increment(T item);
      int count(T item);
      void printSummary();
};

template<class T>
int Counter <T> :: increment(T item){
   bool check = false;

   for(int i=0; i < data.size(itemtype); i++){
      if(data[i].itemtype == item){
         data[i].total++;
         bool check = true;
         break;
      }
   }
   if(check == false){
      data.push_back(itemtype = item, total = 1);
   }
}

int main(){

   Counter<string> counter;   

   counter.increment("orange");
   counter.increment("orange");

   return 0;
}

解决方案

In line for(int i=0; i < data.size(itemtype); i++){

will be: for(int i=0; i < data.size(); i++){

And data.push_back(itemtype = item, total = 1); can be:

1. data.push_back({item, 1}); // by using initializer list ; C++11

2. or,

   Record r; 
   r.itemtype = item; 
   r.total = 1;
   data.push_back(r);
   

You can look at : http://www.cplusplus.com/reference/vector/vector/ to know about std::vector.

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