Example Using the Vector Classes
Example 1 – Using the Vector Classes
FILENAME: example1.cpp
Program:
/*
* Example program using class RWMathVec<double>
* to do simple statistics with double precision vectors.
*/
// Include the RWMathVec<double> class header file.
#include <rw/math/mathvec.h>
#include <iostream>
int main()
{
// Declare the double precision vector V:
RWMathVec<double> V;
// Read the vector from standard input:
std::cin >> V;
/*
* Output the length of the vector.
* This illustrates the use of an RWMathVec<double>
* member function.
*/
std::cout << "The length of the vector is:\t"
<< V.length() << "\n";
/*
* Calculate the mean of the vector.
* This illustrates the use
* of the global function mean().
*/
double avg = mean(V);
std::cout << "The mean of the vector is:\t" << avg << "\n";
/*
* Find the index of the maximum element of
* the vector and output the value.
*/
int maxV = maxIndex(V);
std::cout << "The maximum value of the vector is:\t"
<< V(maxV) << "\n";
// Output the variance of the vector:
std::cout << "The variance of the vector is:\t"
<< variance(V) << "\n";
/*
* Here is how to demean and normalize a
* vector and print out the result.
*/
V -= mean(V); // Remove the mean
maxV = maxIndex(V); // Max element
if ( V(maxV) != 0) {
V /= fabs(V(maxV));
std::cout << "The normalized demeaned vector is:\n" << V;
}
}
Sample Input:
[ 1.33 -23.7 -.23 16.46 9.5
3.14 11.3 -1. 24.23. 12.3 ]
Sample Output:
The length of the vector is: 10
The mean of the vector is: 5.333
The maximum value of the vector is: 24.23
The variance of the vector is: 151.721701
The normalized demeaned vector is:
[
-0.211833 -1.536381 -0.294385 0.588824 0.220511
-0.11605 0.315764 -0.335133 1 0.3686831
]
