Chapter 1
File Extensions: Source file (java), class file (class) No Executable code (exe) code generated in Java.
Java is both a compiler (javac) and an interpreter (java)
JDK – Java Development Kit (includes JRE) is needed to create your own Java classes
Language Elements: keywords, identifiers, operators, punctuation, syntax
Literals – character (char/string) or numeric (integer/floating point).
‘c’ (char) , “c” (char string), 10 (integer), 12. & 16.0 (floating point [double])
A numeric literal without a decimal point is an int.
A numeric literal with a decimal point is a double.
true and false are reserved literals of the bool data type
Variable Declarations
( char, int, float, double, bool )
<data type> <name> [ = value ] ; //initialization is optional
Examples:
int x; int y = 10;
double length = 5.0, double width;
The three primary activities of a program are input, processing, and output
Programming Paradigms: Procedural, Object-oriented, Event-driven ( using an OOP language )
Chapter 2
Preprocessor Directives:
#include
All preprocessor directives begin with a #
preprocessor directives are NOT C++ statements
Function main template:
int main ( )
{
<statements>
return 0;
}
Punctuation Characters: // /* */ # <> ( ) { }
cout object
<<
““
‘‘
;
(stream insertion operator) separate statements / cascaded statement
Common Escape Sequences:
\n (newline)
variables and literals:
X
c++ keywords: ( all lowercase )
‘X’
Note:
\t (tab)
“X”
5
5.0
cin and cout are NOT keywords.
Rules for Identifiers:
legal variable names
first character upper or lower case character a-z or A-Z
remaining characters, a-z, A-Z, 0-9, _ (underscore)
practical limit is 31 characters
Integer data types: short, int, long ( modifier unsigned may be used with integer data types )
Characters:
‘A’
65 (ascii code)
character (char) is a subtype of integer (int)
the ordinal value of a character in the ASCII character set is stored as an integer
Character string Null character
‘\0’
Floating-point data types: float, double, long double
bool data type:
sizeof( ) operator
true
false
sizeof ( int )
sizeof ( GrossPay )
unassigned – “garbage value”
Variable declaration / assignment
Arithmetic operators:
+ - *
/
%
Distinguish between integer and floating point division: 3/5 3.0/5
Remember that the % operator returns the integer remainder of a division
Chapter 3
cin object
>> (stream extraction operator)
Using a single statement / cascaded operators
Whitespace: spaces, tabs, newlines
Reading strings:
cin versus cin.get( ) versus cin.getline( )
Char Arrays: char Array[21] size / room for Null character ‘\0’
Array size declarator must be an integer named constant or integer literal
Array bounds - cin can accept more characters than the array can hold! Array bounds are not checked…
Mathematical expressions – operator precedence
( )
* / %
in order from left to right
+ –
in order from left to right
Type conversion: mixed data types in an expression
promote to highest type found
Type Casting:
C style casting: ( int ) x
C++ typecast:
int ( x )
ANSI standard C++: static_cast<int>(x)
Constants: const keyword:
const double PI = 3.14159;
preprocessor directive:
#define PI 3.14159
Combined Assignment Operators: +=, -=, *=, /=, %=
Output formatting: #include<iomanip>
stream manipulators
fixed, showpoint, setprecision( ), setw( ), left, right
cin member functions
cin.get( ), cin.getline( ), cin.ignore( )
Output mode:
automatic / fixed / scientific
default output mode is automatic
default precision is 6
automatic mode (significant digits ---> integer and decimal positions)
fixed mode (number of decimal positions)
setw( ) stream manipulator
width of output field, right-justifies
setprecision( ) set number of significant digits or decimal digits ( if used with fixed )
fixed
change mode to fixed ( change meaning of setprecision to decimal digits )
showpoint
left / right
Formatted input:
cin >> setw( 8 ) >> X;
cin.getline( array, size )
Math library functions:
#include <cmath>
Math library constants – M_PI and M_E
pseudorandom numbers:
rand( ), srand( ) seed value --> srand( time( NULL ) )
rand( ) % x
--> returns numbers in the range 0 .. x-1
1 + rand( ) % x --> returns numbers in the range 1 .. x
Chapter 4
Relational operators: <
<=
>
>=
==
!=
Evaluate to true ( 1 ) or false ( 0 )
what is true?
Any expression that evaluates to non-zero is considered "true".
if ( -5 ) expression –5 is considered true (its non-zero)
if statement:
if ( expression )
statement;
if/else statement:
if ( expression )
{ statements }
if ( expression-1 )
statement-1;
// don’t forget the ; here!
else
statement-2;
if/else if statement ( case structure ):
if ( expression-1 )
if ( expression-1 )
statement-1;
statement-1;
else
or
else if (expression-2)
if (expression-2)
statement-2;
statement-2;
else if … // two words! else if
else
if ….
Trailing else --- default case. Statement executed when all of the conditions are false.
Nested if statement:
if ( expression-1 )
{
if (expression-2)
statement-2;
}
Logical operators: ! (not)
if ( weight > 0 && weight <= 20 )
correct-weight-statement;
if ( weight <= 0 || weight > 20 )
weight-error-statement;
&& (and)
|| (or)
Connect two or more relational expressions
// test to see if a value is within a specific range
// test to see if a value is outside a specific range
Precedence is 1: ! (not) 2: && (and) 3: || (or)
Variable declarations and scope
{ } block
The scope of a variable is the block in which it is declared.
Variables with the same name ( nested blocks )
conditional operator:
test-expression ? t-expression : f-expression;
x < 0 ? y = 10 : z = 20;
if ( x < 0 )
y = 10;
else
z = 20;
Note: << has higher precedence than ?: (conditional) operator – put conditional expression in ( )
cout << ( (num % 2 == 0) ? “Even\n” : “Odd\n” );
char data type
a single character enclosed in single quotes: ‘a’, ‘b’, ‘\n’, ‘\t’ [escape sequences are a single character]
string class
#include<string>
string description;
string name = “Hector”
supported operators: [ ], relational, comparison, = (assignment)
switch statement:
switch ( integer-expression )
{
case constant-integer-expression : //integer or character literal
statement(s) ;
break (optional) ;
default (optional) :
statements;
}
Checking for file open errors
if ( ! inFile )
if ( inFail.fail( ) )
stream extraction operator returns a value of true or false
if ( inputFile >> number )
can be used to control a loop
while ( inputFile >> number ) // returns true as long as you are not at the end of the file
Note: can be used with cin object [ while ( cin >> number ) ] // returns true while not EOF ( Ctrl-D or Ctrl-Z )
Chapter 5
increment and decrement operators:
++ , – –
prefix and postfix modes
/ using in expressions
++val (1. increment 2. use in expression),
– –val (1. decrement 2. use in expression)
val++ (1. use in expression, 2. increment)
val– – (1. use in expression, 2. decrement
A loop is a block of code that is repeated while some condition is true or until some condition is true.
For any loop, there are three types of expressions which may be necessary
 initialization-expression(s)
used to initialize a loop control variable and any other variables
that need to be initialized before executing a loop
 text-expression
used to determine whether or not the body of the loop should be
executed
 update-expression(s)
used to update a loop control variable ( if present )
while and do...while loops only require a test-expression. A For loop does not require any of these expressions.
while loop [ pre-test loop ]
while (expression)
statement;
executes while expression is non-zero
body of loop executed 0 or more times
while (expression)
{
statement-1;
statement-n;
}
counters ( 228),
accumulators, running totals (231)
sentinel – a special value that marks the end of a list of values. Used to satisfy the condition necessary to terminate a
loop. A sentinel value is outside the range of normal expected values.
while ( Emp_no != -1 )
{
loop body
}
do-while loop [ post-test loop ]
do
do-while loops are often used with menus
body of loop executed at least once
statement;
while (expression);
do {
statement-1;
statement-n;
} while (expression);
for loop [ pre-test loop ]
for ( initialization ; test ; update )
statement;
for ( initialization ; test ; update)
{
statement-1; statement-2;
}
•
•
•
•
•
•
•
statement-n;
only thing required in the parentheses is the semicolons ( ; ; )
initialization is performed once
test is performed every iteration of the loop
update is performed every interation of the loop after the body of the loop has been executed
pre-test loop - executed 0 or more times
may declare local variable(s) in the for loop header
may have multiple expressions separated by commas in the for loop header
for ( int x=2, y=3 ; x*y < =100 ; x++, y++ )
cout << setw(5) << x << setw(5) << y << endl;
Nested loops
for ( int j=0 ; j < 10 ; j++ )
for ( int k=0 ; k<10 ; k++)
cout << j << ‘\t’ << k << ‘\t’ << j+k << endl;
break keyword – used to terminate a loop early
while (1)
{
if ( x = = 10 )
break;
}
continue keyword - causes a loop to stop its current iteration and begin the next one
while (1)
{
if ( x = = 10 )
continue;
}
using a loop for input validation
cout << “Enter a number in the range of 1 – 100: “;
cin >> Number;
while ( Number < 1 | | Number > 100 )
{
cout << “Please enter a number in the range of 1 – 100: “;
cin >> Number;
}
File Input and Output:
3-step process:
1. open the file
2. process the file (read/write)
3. close the file
use of file stream objects requires the fstream header file #include<fstream>
File Stream Classes:
ifstream file used for input (read only)
ofstream file used for output (write only)
fstream file used for input, output or both
Declaration of a File Stream Object:
ifstream Infile;
ofstream outfile;
Use of the Open( ) Member Function:
infile.open(“customer.dat”);
outfile.open(“info.dat”);
use of a backslash in a path for a file specification
OutputFile.open(“a:\\files\\invtry.dat”); // requires two backslashes
closing a file
OutputFile.close( );
writing to a file using the stream insertion operator <<
outfile << “I love C++ programming…”;
using the stream extraction operator to read information from a file
>>
InputFile >> Emp_No;
InputFile >> FirstName;
remember the stream extraction operator stops reading when it encounters any whitespace character ( space, tab,
newline )