Exercise $4.$ For the class Vector, write down the implementation of the method shuffle. On a vector v$,$ v$.$shuffle swaps $v[0]$ and $v[1],v[2]$ and $v[3],$dots. If the size of $v$ is odd, the method does not affect the last element. For example, if $v=\{a,b,c,d,e,f,g\},$ then v$.$shuffle$()$ will return $\{b,a,d,c,f,e,g\}.$

Note: A slightly modified version of the implementation of the class Vector is provided in the file Vector.h that accompanies this assignment. You can build upon that.

$[5$ points$]$