Storing data of two 3-D vectors and computing the dot product

Question

I understand how to store data in a numerical array, but if I had a user input data for 2 three dimensional vectors, how could I then print the dot product of those vectors. Not a homework problem. Just was wondering how I would go about it.

By writing code and applying the (mathematical) operation? Also how is this specific to C++? — UnholySheep, Oct 03 '17 at 14:15
Sounds like you could benefit from reading one of [these C++ books](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list) if it is C++ you want to learn. — Ron, Oct 03 '17 at 14:16

score 1 · Accepted Answer · answered Oct 03 '17 at 19:59

1

for(int i = 0;i < 3;i++)
{
    sum = sum + v[i]*u[i];
}

Here sum has the dot product if u and v are the vectors. Its just a for loop.

answered Oct 03 '17 at 19:59

gst1502

306
1
10

score -1 · Answer 2 · answered Oct 03 '17 at 20:11

This is what I ended up with

#include <iostream>

using namespace std;

int main()
{
    double vec1[3];
    double vec2[3];
    int i;
    double scalar = 0.0;

   cout << "Enter components of vector 1:\n";

   for(i=0;i<3;i++)
   {
       cout << "Component " << i+1 << ": ";
       cin >> vec1[i];
   }

   cout << "Enter components of vector 2:\n";
   for(i=0; i<3; i++)
   {
       cout << "Component " << i+1 << ": ";
       cin >> vec2[i];
   }
    for(i=0; i<3; i++)
    {
    scalar = scalar + (vec1[i] * vec2[i]);
    }

    cout << "The scalar product is " << scalar << endl;

    return 0;
}

Storing data of two 3-D vectors and computing the dot product

2 Answers2