Exercise $0$

We consider an array $a$ of double of size $n,$ an array $b$ of double of size $m.$ Create the following functions that returns $f(a,b,n,m).$

$f(a,b,n,m)={\displaystyle \underset{i=1}{\overset{n}{}}}{\displaystyle \underset{j=1}{\overset{m}{}}}a(i)**b(j)$

Return $f(a,b,n,m)$ with a function.

void function, return the output with a pointer.

void function, return the output with a reference.

Call and test the $3$ functions in the main.