Multiply two user inputted vectors

Assignment.txt

Matrix multiplication: Write a C++ program to compute the product of two matrices. 
You are required to use the template class vector to represent a matrix. 
Specifically, your program will include the main( ) function and a second function multiply_matrices( ). 

The main() function will: 
	* allow the user to choose the size of the matrices, and subsequently the content of A and B
	* call the multiply_matrices() function to compute the product of A and B 
	* print out the multiplication result.

Source

#include <cstdlib>
#include <iostream>
#include <vector>
#include <iomanip>
using namespace std;

void showMatrix(vector <vector<int> > matrix)
{
	for (int i = 0; i < matrix.size(); i++) // i is the row in the matrix
	{
		for (int j = 0; j < matrix[i].size(); j++) // j is the col in the matrix
		{
			cout << setw(3) << matrix[i][j];
		}
		cout << endl;
	}
	cout << endl;
}

vector <vector<int> > vectorMultiply(vector <vector<int> > &matrix1, vector<vector<int> > &matrix2)
{
	vector<vector<int> > result;
	int sum = 0;
	for (int i = 0; i < matrix1.size(); i++)
	{
		vector<int> temp;
		for (int j = 0; j < matrix1[i].size(); j++)
		{
			for (int k = 0; k < matrix1[i*j].size(); k++) //error
			{
				sum = sum + matrix1[i][k] * matrix2[k][j];
				temp.push_back(sum);
			}
			sum = 0;
			result.push_back(temp);
		}
	}

	return result;
}

int main()
{
	int inputSizeFMRow = 0; //input for size of first matrix row
	int inputSizeFMCol = 0; //input for size of first matrix col
	int inputSizeSMRow = 0; //input for size of second matrix row
	int inputSizeSMCol = 0; //input for size of second matrix col
	int userInput = 0; //elements provided by the user
	vector <vector<int> > firstMatrix(inputSizeFMRow);
	vector <vector<int> > secondMatrix(inputSizeSMRow);

	cout << "Please enter the row size of the first matrix: ";
	cin >> inputSizeFMRow;
	cout << "Please enter the column size of the first matrix: ";
	cin >> inputSizeFMCol;
	cout << endl;

	for (int i = 0; i < inputSizeFMRow; i++)
	{
		vector<int> temp;
		for (int j = 0; j < inputSizeFMCol; j++)
		{
			cout << "Please enter values into the first matrix: ";
			cin >> userInput;
			temp.push_back(userInput);
		}
		firstMatrix.push_back(temp);
	}

	cout << "\nPlease enter the row size of the second matrix: ";
	cin >> inputSizeSMRow;
	cout << "Please enter the column size of the second matrix: ";
	cin >> inputSizeSMCol;
	cout << endl;

	if (inputSizeFMCol != inputSizeSMRow)
	{
		cout << "These matrices cannot be multiplied together.\n";
	}
	else
	{
		for (int i = 0; i < inputSizeSMRow; i++)
		{
			vector<int> temp;
			for (int j = 0; j < inputSizeSMCol; j++)
			{
				cout << "Now please enter the values for the second matrix: ";
				cin >> userInput;
				temp.push_back(userInput);
			}
			secondMatrix.push_back(temp);
		}
		vector <vector<int> > multiMatrix = vectorMultiply(firstMatrix, secondMatrix);
		showMatrix(multiMatrix);
	}

	return 0;
}