Introduction to Java Programming Comprehensive Version 10th

Introduction to Java Programming, Comprehensive Version (10th Edition)

Methods And Arrays

You are given two arrays that represent the components of a vector as shown here.

double[] vec1 = {0.5,0.6,0.2};

double[] vec2 = {1.0,0.0,0.2};

a. Write a method named computeDotProduct that will take in two double arrays (a,b) as parameters and returns a double value.

b. The dot product is the sum of the products of each pair of elements in the two vectors. Set dotProduct equal to 0. Use a loop to sum go through each element in the array. (Hint: dotProduct = dotProduct + a[i]*b[i])

c. Make the method flexible enough that it will accept the arrays of various lengths and will check that the array arguments are of the same length. (Hint: Use a property of the array).

d. Call this method from within the main with the two arrays vec1 and vec2 as arguments.

Solution

public class dotproduct
{
   public static void main(String[] args)
   {
       double[] vec1 = {0.5,0.6,0.2};
       double[] vec2 = {1.0,0.0,0.2};
       double dotProduct = computeDotProduct(vec1,vec2);
       System.out.println(\"Dot Product : \" + dotProduct);
   }
  
   public static double computeDotProduct(double[] vec1, double[] vec2)
   {
       int m = vec1.length;
       int n = vec2.length;
       double dotProduct = 0;
       if(m == n)
       {
           for(int i = 0; i< m; i++)
               for(int j = 0; j< n; j++)
                   dotProduct += vec1[i]*vec2[j];
       }
       return dotProduct;
   }
}