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copied!<p>Here is the code that you should have. I see you have used class in your code, which you do not really need here. Let me know if the question required you to use class.</p> <p>As you are new and this code might scare you. So, I will try to explain this as I go. Look for comments in the code to understand what is being done and ask if you do not understand.</p> <pre><code>//Scalar.cpp #include <stdlib.h> #include <iostream> #include <vector> using namespace std; /** This function returns the scalar product of two vectors "a" and "b" */ double scalar_product(vector<double> a, vector<double> b) { //In C++, you should declare every variable before you use it. So, you declare product and initialize it to 0. double product = 0; //Here you check whether the two vectors are of equal size. If they are not then the vectors cannot be multiplied for scalar product. if(a.size()!=b.size()){ cout << "Vectors are not of the same size and hence the scalar product cannot be calculated" << endl; return -1; //Note: This -1 is not the answer, but just a number indicating that the product is not possible. Some pair of vectors might actually have a -1, but in that case you will not see the error above. } //you loop through the vectors. As bobo also pointed you do not need two loops. for (int i = 0; i < a.size(); i++) { product = product + a[i]*b[i]; } //finally you return the product return product; } //This is your main function that will be executed before anything else. int main() { //you declare two vectors "veca" and "vecb" of length 2 each vector<double> veca(2); vector<double> vecb(2); //put some random values into the vectors veca[0] = 1.5; veca[1] = .7; vecb[0] = 1.0; vecb[1] = .7; //This is important! You called the function you just defined above with the two parameters as "veca" and "vecb". I hope this cout is simple! cout << scalar_product(veca,vecb) << endl; } </code></pre> <p>If you are using an IDE then just compile and run. If you are using command-line on a Unix-based system with g++ compiler, this is what you will do (where Scalar.cpp is the file containing code):</p> <pre><code>g++ Scalar.cpp -o scalar </code></pre> <p>To run it simply type</p> <pre><code>./scalar </code></pre> <p>You should get <code>1.99</code> as the output of the above program.</p>

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