Syntax Comparison

Students

This is a comparison of the syntax of some popular programming languages, including Scala which we will be using on 5CS004. Where you see the word "TODO", please collaborate to fill in the blank parts of the tables. We will be adding to this page as the module progresses.

Useful language references

• PHP 5
• Scala
• Java 6
• Python 2.7

Basics

	PHP	Java	Scala	Python
Single line comment	// comment	// comment	// comment	# comment
Multi-line comment	/* comment */	/* comment */	/* comment */	Doesn't have multi-line comments.
Null object	NULL	null	TODO	None
Arithmetic operators	+,-,*,/,%,*	+,-,*,/,%,*	+,-,*,/,%,*	+,-,*,/,%,*
True and false	TRUE, FALSE	true, false	TODO	True, False
Boolean operators	&&, ||, !	&&, ||, !	TODO	and, or, not
Relational operators	<, >, <=, >=, ==, !=	<, >, <=, >=, ==, !=	<, >, <=, >=, ==, !=	<, >, <=, >=, ==, !=

Input / output

	PHP	Java	Scala	Python
Print to console	echo("hello");	System.out.println("Hello");	TODO	print "Hello"
Read from keyboard	readline("")	BufferedReader in = new BufferedReader(new InputStreamReader(System.in)); String kbd = in.readLine();	val kbd = readLine()	kbd = raw_input() # kbd is a string kbd = input() # kdb may be some other type

Selection

	PHP	Java	Scala	Python
if/else	if ($a==$b) { echo("same"); } else { echo("different"); }	if (a==b) { System.out.println("same"); } else { System.out.println("different"); }	TODO	if a==b: print 'same' else: print 'different'
else-if	if ($a<0) { echo("negative"); } elseif ($a==0) { echo("zero"); } else { echo("positive"); }	TODO	TODO	if a<0: print 'negative' elif a==0: print 'zero' else: print 'positive'
switch	switch ($i) { case 0: echo "i equals 0"; break; case 1: echo "i equals 1"; break; case 2: echo "i equals 2"; break; }	switch ($i) { case 0: System.out.println("i equals 0"); break; case 1: System.out.println("i equals 1"); break; case 2: System.out.println("i equals 2"); break; }	TODO	Python has no switch statement. Use "if" instead.

Iteration

	PHP	Java	Scala	Python
for	TODO	TODO	TODO	TODO
foreach	TODO	TODO	TODO	TODO
while	TODO	TODO	TODO	TODO

Functions

	PHP	Java	Scala	Python
Defining functions	function($msg) { echo $msg; }	No equivalent. Use methods instead.	TODO	def print_msg(msg): print msg

Compound types (arrays, lists, etc)

	PHP	Java	Scala	Python
Fixed length array	TODO	TODO	TODO	TODO
Mutable array	TODO	TODO	TODO	TODO
Associative arrays / hashes	TODO	TODO	TODO	TODO

Exception handling

	PHP	Java	Scala	Python
Raise an exception	throw new Exception("Division by zero");	throw new ClassNotFoundException();	TODO	raise ValueError()
Handle / catch an exception	TODO	TODO	TODO	TODO

Dealing with types

	PHP	Java	Scala	Python
Convert object to different type	TODO	TODO	TODO	TODO

Classes, objects, methods, etc

	PHP	Java	Scala	Python
TODO	TODO	TODO	TODO	TODO