不存在合适的构造函数 - 矢量图

问题描述

我今天为自己开始了一个简单的编码项目，但我无法弄清楚这个错误或如何解决它。我遇到的错误发生在我的 do 循环中。更具体地说，它发生在每个将 Nums 作为参数传递的函数调用中。错误状态 no suitable constructor exists to convert from to "std::vector<int,std::allocator<int>> [10]" to "std::vector<int,std::allocator<int>>"

对此的任何帮助将不胜感激！ TIA！

//This program checks to see if a multiplied vector value is odd or even
//CheckOddEven.cpp

#include <iostream>
#include <vector>
#include <numeric>

using namespace std;

int setSize(int size,vector <int> Nums) //Sets vector size to user defined size
{
        //Prompt user to enter an integer to establish array size
        cout << "How many integers would you like to multiply?: ";

        //Store user input to size
        cin >> size;

        //Resize vector to user size
        Nums.resize(size);

        return size;
}

vector <int> setNum(int size,int x,vector <int> Nums) //Sets values in each index
{
        //Insertion loop to Nums vector
        for (int i = 0; i < size; i++)
        {
                cout << "Enter integer #" << i + 1 << ": ";
                cin >> x;
                Nums.push_back(x); //Assigns value into vector
        }

        return Nums;
}

int doMath(vector <int> Nums,int result)
{
        //Loop through Nums vector and multiply all values
        accumulate(Nums.begin(),Nums.end(),result,multiplies<int>());

        return result;
}

string oddEven(int result,string msg) //Check if int is even by seeing if there is a remainder
{
        //If no remainder exists then positive
        if (result % 2 == 0)
                {
                        msg += "positive.";
                }
                
        //If remainder exists then negative
        else
        {
                msg += "negative.";
        }

        return msg;
}

void display(int result,string msg)
{
        cout << "The product of your integers is " << result << endl;
        cout << msg;
}

char checkCont(char cont)
{
        //Asks user if they want to check another integer
        cout << "Would you like to check another? (y/n)" << endl;

        //Assigns input as char into cont
        cin >> cont;

        //displays exit message and ends do-while
        if (cont == 'n' || cont == 'N')
        {
                cout << "Thank you for using the Odd-Even Checker!" << endl;
                cout << "Have a great day!" << endl;
        }

        return 'z';
}

int main()
{
        int size; //User defined vector size
        string msg = "The number you calculated is ";
        char cont = ' '; //Char value for checking another vector
        vector <int> Nums[10]; //Create int vector with predetermined size..can be changed with resize
        int x; //User numbers
        int result;

        cout << "Welcome to the Odd-Even Checker!" << endl;
        cout << "This program multiplies a given amount of numbers,then checks to see if the answer is even or odd." << endl;

        do //Requires to run at least once
        {
                setSize(size,Nums);
                setNum(size,x,Nums);
                doMath(Nums,result);
                oddEven(result,msg);
                display(result,msg);
                checkCont(cont);
        } while (cont == 'y' || cont == 'Y'); //end do-while

        return 0;
}

解决方法

您声明了一个向量数组

vector <int> Nums[10];

但将此数组传递给需要向量类型标量对象的函数

int setSize(int size,vector <int> Nums);

//...

setSize(size,Nums);

也许不是数组，而是一个包含 10 个元素的向量，例如

vector <int> Nums(10);

或者只是一个空向量

vector <int> Nums;

似乎还存在一个问题，即您没有通过引用传递向量。例如，函数 setSize 处理传递的向量的副本。

结果是函数内的这个语句

Nums.resize(size);

没有意义。

在需要引用类型的函数中将向量函数参数的类型更改为像

int setSize(int size,vector <int> &Nums);
                                  ^^^^^^

注意函数内部没有使用参数size的值，所以参数size没有意义。

这个功能也没有意义

int doMath(vector <int> Nums,int result)
{
        //Loop through Nums vector and multiply all values
        accumulate(Nums.begin(),Nums.end(),result,multiplies<int>());

        return result;
}

调用算法std::accumulate后变量结果没有改变。

您还传递了一个未初始化的变量结果

int result;

你至少应该写

long long int doMath( const std::vector<int> &Nums )
{
        //Loop through Nums vector and multiply all values
    long long result = std::accumulate(Nums.cbegin(),Nums.cend(),1ll,std::multiplies<long long>());

    return result;
}

您应该将您的程序拆分成小的子程序并分别测试每个使用的功能，因为您似乎不明白自己在做什么。之后，您可以将所有子程序合并为一个程序。

例如要测试函数setSize，您可以编写这样的简单程序

#include <iostream>
#include <vector>

std::vector<int>::size_type setSize( std::vector<int> &Nums )
{
    //Prompt user to enter an integer to establish array size
    std::cout << "How many integers would you like to multiply?: ";

    //Store user input to size
    std::vector<int>::size_type size = 0;
    std::cin >> size;

    //Resize vector to user size
    Nums.resize( size );

    return size;
}

int main() 
{
    std::vector<int> Nums;
    
    auto size = setSize( Nums );
    
    if ( size == Nums.size() )
    {
        std::cout << "The function works correctly.\n";
    }
    else
    {
        std::cout << "Something is wrong with the function!\n";
    }
    
    return 0;
}

在您确定该功能按预期工作后，您可以将其添加到主程序中。