Simple Deadfish Interpreter.

Deadfish is a simple language that only has 4 instructions:

1. 'i' is responsible for incrementing by one.
2. 'd' is responsible for decrementing by one.
3. 's' is responsible for squaring the number.
4. 'o' is responsible for printing the output.

to run the code:

cd deadfish_interpreter
cargo run

try running these instructions: iiodddoisoisoiso
It should output:

2
0
1
4
25