Running code, with input

Run bash, python and javascript blocks where they are written, and keep the output in the note.

Running a block

1. Type /code and pick the language from the dropdown on the block.
2. Press Run. The output is written into an output block underneath, stamped with when it ran. Running again replaces it.

Programs that ask for input

A program that reads input — input() in Python, read in a shell, process.stdin or readline in JavaScript — needs its answers before it runs, because nobody is at a keyboard inside the machine it runs on.

```python
name = input("What is your name? ")
age = int(input("How old are you? "))
print(f"Hello {name}, next year you will be {age + 1}")
```

1. Press Run. ForkLeaf sees the program reads input and opens Program input instead of running it.
2. Type the answers, one per line — here Ada, then 36.
3. Press Run again. Each line is what the program reads the next time it asks.

• Input in the block’s header opens or closes the box at any time. It shows Input ✓ when there is something in it.
• If a program stops because it ran out of input, the box opens and says so. Add the missing lines and run again.
• The input is not saved in the note — only the output is.

Where the code runs

In a throwaway virtual machine made for the one run and destroyed afterwards — never on your computer. It has internet access, and a run can take up to 30 seconds.