Comparison of programming languages (basic instructions)

Data types

How to declare variable x as the following types:

	Integer	Unsigned integer	Float	String
C	int x;	unsigned int x;	float x; or double x;	char x[]; or char *x;
C++ (STL)	int x;	unsigned int x;	float x; or double x;	string x;
Java	int x;		float x; or double x;	String x;
Pascal	var x: integer;	var x: word;	var x: real;	var x: string;
Visual Basic	Dim x as Integer		Dim x as Single or Dim x as Double	Dim x as String
Python	x = value	x = value	x = value	x = "string"
S-Lang	x = value	x = value	x = value	x = "string"

Logical cycles

	if	else if	while	do while	for i = 1 to N	select case
C	if (condition) { instructions } else { instructions }	if (condition) { instructions } else if (condition) { instructions }	while (condition) { instructions }	do { instructions } while (condition)	for (i = 0; i<N; i++) { instructions }	switch (variable) { case case1: instructions break; ... default: instructions;}
C++ (STL)	as above	as above	as above	as above	as above	as above
Java	as above	as above	as above	as above	as above	as above
Pascal	if condition then begin \n instructions \n end;	if condition then begin \n instructions \n end\n else begin \n instructions \n end;		repeat \n instructions \n until condition;	for i := 1 to N do \n begin \n instructions \n end;	case variable of \n meaning: instructions; \n default: instructions \n ... end;
Visual Basic	If condition Then \n instructions \n Else instructions \n End If	If condition Then \n instructions \n ElseIf condition Then \n instructions \n Else instructions \n End If	Do While condition \n instructions \n Loop	Do \n instructions \n Loop While condition	For i = 1 To N Step 1 \n instructions \n Next i	Select Case variable \n Case case1 \n statements \n ... Case Else \n Statements \n End select
Python	if condition : \n \t instructions \n else: \n \tinstructions \n				for i in range(1, N): \n \t instructions \n
S-Lang	if (condition) { instructions } else { instructions }	if (condition) { instructions } else if (condition) { instructions }	while (condition) { instructions }		for (i = 0; i<N; i++) { instructions }	switch (variable) { case case1: instructions } { case case2: instructions } ...

Function declaration

	basic	value-returning function
C	void foo(parameters) { }	type foo(parameters) { }
C++ (STL)	as above	as above
Java	public or private + as above	public or private +as above
Pascal	procedure foo(...);	function foo(...):type;
Visual Basic	Sub foo(parameters)	Function foo(parameters) As type
Python	def foo(parameters): \n \t instructions \n	add return value at the end.
S-Lang	define foo (parameters ; qualifiers) { }	define foo (parameters ; qualifiers) { ... return value; }

Data conversions

	string to integer	string to float	integer to string	float to string
C	integer = atoi(string);	float = atof(string);	sprintf(string, "%i", integer);	sprintf(string, "%f", float);
C++
Java	integer = Integer.parseInt(string);	float = Float.parseInt(string);	string = integer;	string = float;
Pascal	integer := StrToInt(string);	float := StrToFloat(string);	string := IntToStr(integer);	string := FloatToStr(float);
Visual Basic	integer = CInt(string)	float = CSng(string) or double = CDbl(string)	string = CStr(integer)	string = CStr(float)
Python	int('5')	float('5.0')	str(5)	str(5.0)
S-Lang	integer = atoi(string);	float = atof(string);	string = string(integer);	string = string(float);

Standard Input and Standard Output

	stdin	stdout	stderr
C	scanf( ... ); fscanf(stdin, ... );	printf( ... ); fprintf(stdout, ... );	fprintf(stderr, ... );
C++	cin >> x;	cout << x;	cerr << x;
Java	x = System.in.read();	System.out.print(x);	System.err.print(x);
Pascal	read( ... ); readln( ... );	write( ... ); writeln( ... );	var IOResult;
Visual Basic	input	print x	?
Python	For numbers: x = input() For strings: x = raw_input()	print( ... ) sys.stdout.write( string )	sys.stderr.write( string )
S-Lang	fgets (&x, stdin)	fputs (x, stdout)	fputs (x, stderr)

Reading arguments

	Argument values	Argument counts
C	char **argv	int argc
C++	as above	as above
Java	string = args[x];	integer = args.length;
Pascal	string := ParamStr(integer);	integer := ParamCount;
Visual Basic
Python	sys.argv	len(sys.argv)
S-Lang	__argv	__argc