Write a program to calculate the total size $($in bytes, no text or commas, just the integer answer$)$ of all files in the current directory$/$folder and all sub$-$folders. Write this program in $3$ different languages separately: $1)$ Python $2)$ Java $3)$ C$.$ Your code must include a recursive function written and called by the student; this means the library function $\text{'}$os$.$walk$()\text{'}$ is not allowed when using Python.