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Software Design Using C++

Useful Tables: Precedence Chart, Data Types, and Library Functions

Operator Precedence Chart

We need to know which operator comes first when writing arithmetic expressions in our C++ programs. The most common arithmetic operators follow the same precedence rules as in algebra. However, C++ includes additional operators not found in ordinary algebra. The following table shows many (but not all) of the C++ operators for arithmetic, logical operations, etc. Those with priority 1 are handled before all of those with a larger precedence number. Those with priority 2 come after those with priority 1 but before all of the others. Those with the same priority are generally handled in a left to right fashion. Parentheses can be used to group items so that whatever is inside is handled before other items. If there are parentheses inside of parentheses it is the innermost set of parentheses that is handled first.

Operator	Description	Precedence
()	function call	1
[]	array indexing	1
++ after a variable	postincrement	1
-- after a variable	postdecrement	1
!	Boolean NOT	2
++ before a variable	preincrement	2
-- before a variable	predecrement	2
- before an expression	unary minus	2
*	multiply	3
/	divide	3
%	remainder (mod)	3
+	add	4
-	subtract	4
<	less than	5
>	greater than	5
<=	less than or equal	5
>=	greater than or equal	5
==	equal	6
!=	not equal	6
&&	Boolean AND	7
\|\|	Boolean OR	8
=	assignment	9
+= (and similar)	add and assign	9

Data Types

There are many data types available in C++, and the programmer can also define new ones by setting up appropriate classes (as covered in the Intermediate and Advanced sections of these Software Design Using C++ web pages. The table below lists many of the data types commonly available to the C++ programmer. Note that you can find more information about most of these types by looking up certain articles in the Visual Studio help system. Also, notice that the "Section" column indicates in what section of these C++ web pages each data type is covered, thus giving a rough idea of the level of difficulty.

Type	Description	Section	Visual Studio Help System Articles	Further Information
int	integer	introductory	Fundamental Types, Data Type Ranges	discussion, example
char	character	introductory	Fundamental Types, Data Type Ranges	discussion, example
float	floating point number	introductory	Fundamental Types, Type float, Data Type Ranges	discussion, example
long	long integer	intermediate	Fundamental Types, Data Type Ranges	discussion, more
double	double precision float	not covered	Fundamental Types, Type float, Data Type Ranges
bool	Boolean	introductory	Fundamental Types	discussion
char array	C-style char array string	introductory		discussion, more, example, security
Class string	a string class	advanced	string	discussion, example
Class CString	another string class	advanced	Basic CString Operations	discussion

Library Functions

Lots of built-in library functions are available for your use. The table below presents summary information about some of the most commonly-used ones. The "header" column indicates what header file (if any) needs to be included in order to use each function. Note that this can vary somewhat from compiler to compiler.

Function	Description	Header
double pow(double, double)	returns first parmeter to power of second parameter	cmath
int abs(int)	returns absolute value of parameter	cstdlib
double abs(double)	returns absolute value of parameter	cmath
double sqrt(double)	returns square root of parameter	cmath
double exp(double)	returns e to power of parameter	cmath
double log(double)	returns base e log of parameter	cmath
double log10(double)	returns base 10 log of parameter	cmath
double sin(double)	returns sine of parameter	cmath
double cos(double)	returns cosine of parameter	cmath
double tan(double)	returns tangent of parameter	cmath
double asin(double)	returns Arcsine of parameter	cmath
double acos(double)	returns Arccosine of parameter	cmath
double atan(double)	returns Arctangent of parameter	cmath
int srand(unsigned int)	seeds random number generator with parameter	cstdlib
int rand()	returns a pseudorandom int between 0 and RAND_MAX	cstdlib
strcat(char_array_variable, char_array_expression)	appends second parameter to end of first parameter	cstring
strcpy(char_array_variable, char_array_expression)	copies second parameter to first parameter	cstring
strcmp(char_array_expression, char_array_expression)	returns 0 if equal, negative if first less than second, positive otherwise	cstring
integer strlen(char_array_expression)	returns number of characters in parameter	cstring
bool isalpha(char)	returns true if parameter is a letter	cctype
bool isdigit(char)	returns true if parameter is a digit	cctype
bool isalnum(char)	returns true if parameter is letter or digit	cctype
bool isupper(char)	returns true if parameter is a uppercase letter	cctype
bool islower(char)	returns true if parameter is a lowercase letter	cctype
int toupper(char)	returns uppercase version of parameter	cctype
int tolower(char)	returns lowercase version of parameter	cctype
int atoi(const char_array)	returns parameter converted to an integer	cstdlib
double atof(const char_array)	returns parameter converted to a double	cstdlib

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Author: Br. David Carlson with contributions by Br. Isidore Minerd
Last updated: August 27, 2009
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