No Suitable Constructor Exists - Vector - c++

Question

I started a simple coding project for myself today and I cannot figure out this error or how to combat it. The error I am getting occurs during my do loop. More specifically, it occurs with each function call that passes Nums as a parameter. The error states no suitable constructor exists to convert from to "std::vector<int, std::allocator<int>> [10]" to "std::vector<int, std::allocator<int>>"
Any help on this would be greatly appreciated! 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;
}

Answer 1

You declared an array of vectors
vector <int> Nums[10];
but passing this array to functions that expects a scalar object of the vector type
int setSize(int size, vector <int> Nums);
//...
setSize(size, Nums);
Maybe instead of the array you mean a vector with 10 elements like
vector <int> Nums(10);
or just an empty vector
vector <int> Nums;
It seems there exists one more problem that you are not passing the vector by reference. So for example the function setSize deals with a copy of the passed vector.
As a result this statement within the function
Nums.resize(size);
does not make a sense.
Change the type of the vector function parameter in functions where it is required to a referenced type like
int setSize(int size, vector <int> &Nums);
^^^^^^
Pay attention that the value of the parameter size is not used within the function, So the parameter size does not make a sense.
Also this function does not make a sense
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;
}
the variable results is not being changed after calling the algorithm std::accumulate.
Also you are passing an uninitialized variable result
int result;
You should at least write
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;
}
You should split your program into small sub-programs and test each used function separately because it seems you do not understand what you are doing. After that you can combain all sub-programs in one program.
For example to test the function setSize you could write a simple program like this
#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;
}
After you will be sure that the function works as expected you can add it to the main program.