Input & Output
Output
| Statement | Description |
|---|---|
print <value> | Print a value without a trailing newline |
println <value> | Print a value followed by a newline |
print 'Loading...'
println 'done'
Input
Input statements write into an existing variable, referenced with a leading &:
| Statement | Description |
|---|---|
inputInt &var | Read a line from stdin, parse it as an integer, store it in var |
inputStr &var | Read a whitespace-delimited token from stdin, store it in var |
age = 0
print 'Enter your age: '
inputInt &age
println age
name = ''
print 'Enter your name: '
inputStr &name
println name
Every example in this book assigns a placeholder value (age = 0, name = '') before reading into a variable with inputInt/inputStr. This isn’t strictly required by the compiler — a variable is registered the first time it’s seen, wherever that is — but it’s good practice: it documents the variable’s intended type up front and avoids relying on whatever default the VM gives an unseen variable.
If inputInt receives text that can’t be parsed as an integer, it prints Invalid value! and leaves the variable at 0.