$1\mathrm{.}11\mathrm{.}2$: Outputting all combinations.

Output all combinations of character variables a$,$ b$,$ and c$,$ in the order shown below. If a $=\text{'}$x$\text{'},$ b $=\text{'}$y$\text{'},$ and c $=\text{'}$z$\text{'},$ then the output is:

xyz xzy yxz yzx zxy zyx

Your code will be tested in three different programs, with a$,$ b$,$ c c$++$