c++ - 通过模板函数 C++ 的引用传递

Question

我正在尝试制作一个模板函数并通过引用将两个变量传递给它，一切听起来都不错，但它从未编译过，错误消息是:-

error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

我试了一小部分代码，它给了我同样的错误，请帮忙吗？？

这部分代码，所有其他代码都是这样的:

int size , found = -1 ; 

template<class type> Read_Data( type &key , type &arr)
{ 
    cout << " please enter the size of your set \n " ; 
    cin >> size ;
    arr = new type[size]; 

    cout << " please enter the elements of your set : \n " ;
    for (int i = 0 ; i <size ; i ++ )
    {
        cout << " enter element number " << i << ": "  ;  
        cin >> arr[i] ;
    }
    cout << " please enter the key elemente you want to search for : \n " ;
    cin >> key ; 
}

void main(void)
{ 
    int key , arr ; 
    Read_Data (key, arr);

    /*after these function there is two other functions one to search for key 
    in array "arr" and other to print the key on the screen */ 
}

Answer 1

您只是缺少一些东西来编译代码(解决您看到的错误)。

基本上，在int main()中，需要在实例化模板时指定类型，如:

Read_Data <int> (key, value); 

这样编译器就知道你真正想用什么类型来实例化它。

另请注意，数组的类型应为 int *。所以在模板函数中，签名必须更改为:

template<class type> Read_Data( type &key , type* &arr)

这是更正后的代码，不会显示您之前看到的错误:

#include<iostream>  

using namespace std;

int size , found = -1 ; 

template<class type> void Read_Data( type &key , type* &arr)
{ 
    cout << " please enter the size of your set \n " ; 
    cin >> size ;
    arr = new type[size]; 
    cout << " please enter the elements of your set : \n " ;

    for (int i = 0 ; i <size ; i ++ )
    {   
        cout << " enter element number " << i << ": "  ;   
        cin >> arr[i] ;
    }   

    cout << " please enter the key elemente you want to search for : \n " ;
    cin >> key;                                                                                                                                         
}

int main()
{   
    int key;
    int * arr;
    Read_Data<int> (key, arr);

    /* after these function there is two other functions one to search for key 
     * in array "arr" and other to print the key on the screen 
     */ 
}