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<TITLE>Data Structures - Lecture 2</TITLE>
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<META NAME="AUTHOR" CONTENT="Alok Mehta">
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<H1>Data Structures - Lecture 2</H1>
<UL>
<LI>C++ Review, Basic Data Types
</UL>
<H1>Topics</H1>
<UL>
<LI>Hello World!
<LI>Data Types, Arrays, Pointers, Functions
<LI>Operators, Expressions, Statements
<LI>Input/Output
<LI>Examples
<LI>Conventions for C++ Programs/Projects
<LI>(Optional) Exercises
</UL>
<H1>References</H1>
<UL>
<LI>[W] = Weiss, Algorithms, Data Structures, and Problem Solving
with C++.
<LI>[H] = Harbison and Steele, C: A Reference Manual, Prentice
Hall.
<LI>[O] = Osborne, C++: The Complete Reference.
<LI>[M] = Musser, Saini, STL Tutorial and Reference Guide.
</UL>
<H1>Topics</H1>
<H1>Hello World!</H1>
<UL>
<LI>Reference: [W:Appendix A.1]
</UL>
<H1>Hello World - Source Code</H1>
<UL>
<LI><TT>/* File: Hello.cpp */</TT>
<LI>#include <iostream.h>
<LI>void main()
<LI>{
<LI> cout << "Hello World"<< endl;
<LI>}
</UL>
<H1>Hello World - Compile/Execute</H1>
<UL>
<LI>Compile "Hello World!":<BR>
% g++ -o hello hello.cpp
<LI>
<LI>Execute "Hello World!"<BR>
% hello
</UL>
<H1>Topics</H1>
<UL>
<LI>Data Types, Arrays, Pointers, Functions
<LI>Reference: [W:Chapter 1, Appendix A]; [H]
</UL>
<H1>Data Types - Type Categories</H1>
<H1>Void Type</H1>
<UL>
<LI>Void is a special type.
<LI>Represents the absence of a data type.
<LI>A pointer to a void (void *) is treated as a generic pointer.
<LI>Examples:
<UL>
<LI>void main () { … }
<LI>void * generic_pointer;
</UL>
</UL>
<H1>Integral Types</H1>
<UL>
<LI>[signed] char, [unsigned] short [int], [unsigned] int, [unsigned]
long [int]
<LI>unsigned char, unsigned short [int], unsigned int, unsigned
long [int]
<LI>Examples:
<LI>signed int index = 7;
<LI>unsigned long l;
<LI>int i,j;
</UL>
<H1>Floating Point Types</H1>
<UL>
<LI>double
<LI>float
<LI>long double
<LI>Examples:
<LI>const double pi = 3.14159;
<LI>extern float x1,y1,x2,y2;
<LI>static double y;
</UL>
<H1>Enumeration Types</H1>
<UL>
<LI>Examples:
<LI>enum fish { trout, carp, halibut } my_fish;
<LI>enum boolean { true, false } success;<BR>
success = true;
<LI>enum color { red, green blue};<BR>
...<BR>
enum color my_favorite, your_favorite;
</UL>
<H1>Pointer Types (Example)</H1>
<UL>
<LI>int i = 5;
<LI>int * ptr;
<LI>ptr = &i;
<LI>i = 7;
<LI>(*ptr) = 2;
</UL>
<H1>Array Types (Example)</H1>
<UL>
<LI>double expenditure[365];
<LI>double * ptr_expenditure = expenditure;
<LI>expenditure[0] = 75.64;
<LI>*ptr_expenditure = 32.45;
<LI>expenditure[20] = 12.87;
<LI>ptr_expenditure[20] = 17.49;
<LI>
</UL>
<H1>Function Types</H1>
<UL>
<LI>Definition Example:<BR>
int square (int x) { return x * x; }
<LI>Declaration Example:<BR>
extern int square (int x);<BR>
static int square (int x);
<LI>Other examples:<BR>
extern int f(), (*fp)(), (*apf[])();
</UL>
<H1>Function Example</H1>
<UL>
<LI>int my_strlen (char * s) {
<LI> char * ps = s;
<LI> int cnt = 0;
<LI> if (s == NULL) { return 0; }
<LI> while (*ps != NULL) { cnt++; ps++; }
<LI> return cnt;
<LI>}
</UL>
<H1>Functions in C++</H1>
<UL>
<LI>Overloading of Function Names<BR>
int Max(int A, int B);<BR>
float Max (float * floatArray, int sz)
<LI>Default Parameters<BR>
float Log (float x, double base=10);<BR>
log(100) // Log 100 base 10<BR>
log(100,2) // Log 100 base 2
<LI>Inline Functions<BR>
inline int Max(int A, int B) { return (A<B ? B : A); }
</UL>
<H1>Topics</H1>
<UL>
<LI>Operators, Expressions, Statements
<LI>Reference: [W:Appendix A] [H]
</UL>
<H1>Operators</H1>
<UL>
<LI>Assignment
<LI>Binary
<LI>Unary
<LI>Relational
<LI>Logical
<LI>Bit
<LI>Misc
</UL>
<H1>Assigment Operators</H1>
<UL>
<LI>Common Operators:<BR>
<TT>=, +=, -=, *=, /=</TT>
<LI>Examples:
<LI><TT>int i,j, k;</TT>
<LI>i = 4
<LI>j = k = 3;
<LI>j += 4;
<LI>i *= 2;
</UL>
<H1>Binary Arithmetic Operators</H1>
<UL>
<LI>Common Operators:<BR>
<TT>+, -, *, /, %</TT>
<LI>Examples:
<LI><TT>3 + 5</TT>
<LI>i * 2 + x / y + 10 % 3
</UL>
<H1>Unary Operators</H1>
<UL>
<LI>Common Operators:<BR>
<TT>-, +, ++, --</TT>
<LI>Examples:<BR>
<TT>X = -2<BR>
Y = -X<BR>
Z = +X<BR>
W = -(X++) + (--Y) + (Z++)</TT>
</UL>
<H1>Relational Operators</H1>
<UL>
<LI><TT>==, !=, <, >, <=, >=</TT>
<LI>Examples:
<LI><TT>s == 0</TT>
<LI>a < b
<LI>(a < b < c) // Not as expected!
<LI>if (s=0) {…} // Not as expected!
</UL>
<H1>Logical Operators</H1>
<UL>
<LI><TT>&&, ||, !</TT>
<LI>Examples:
<LI><TT>if ((a<b) && (c<d)) { … }</TT>
<LI>"Short Circuit" Evaluation
<LI><TT>if ((X!=0) && (1/X != 3)) { … }</TT>
</UL>
<H1>Bit Operators</H1>
<UL>
<LI><TT>~, <<, >>, &, ^, |<BR>
~=, <<=, >>=, &=, ^=, |=</TT>
<LI>Examples
<LI><TT>1 << 4 // 10000</TT>
<LI>3 & 5 // 011 AND 101 = 001
</UL>
<H1>Misc. Operators</H1>
<UL>
<LI>Comma<BR>
<TT>for (i=1,j=2; i<5; i++,j++)</TT>
<LI>Conditional<BR>
N = (s==NULL ? "<NULL>" : s)<BR>
MIN = (X <= Y ? X : Y)
<LI>sizeof(type)<BR>
sizeof(int)
</UL>
<H1>Expressions</H1>
<UL>
<LI>Example: <TT>a * b + c</TT>
<LI>l-value (updatable)
<LI>r-value (read-only)
<LI>Precedence
<LI>Can call other functions
<LI>Side effects
</UL>
<H1>Statements</H1>
<UL>
<LI>if
<LI>while
<LI>do
<LI>for
<LI>switch
<LI>break/continue
</UL>
<H1>If Statement</H1>
<UL>
<LI>Syntax 1:<BR>
if ( <expr> ) statement<BR>
next statement
<LI>Syntax 2:<BR>
if ( < expr> ) <BR>
statement<BR>
else<BR>
statement<BR>
next statement
<LI>Example: if (x==0) x=x+1;
</UL>
<H1>While Statement</H1>
<UL>
<LI>Syntax<BR>
while ( <expr> ) statement<BR>
next statement
<LI>Example<BR>
while (*ps != NULL) { <BR>
cnt++; <BR>
ps++; <BR>
}
</UL>
<H1>Do Statement</H1>
<UL>
<LI>Syntax<BR>
<CODE>do<BR>
statement<BR>
while (expression);</CODE>
<LI>Example<BR>
do {<BR>
prompt_user("Enter value: ");<BR>
response = read_value();<BR>
} while (! is_valid(response));
</UL>
<H1>For Statement</H1>
<UL>
<LI><TT>for (init; test; assignment)<BR>
statement<BR>
next statement</TT>
<LI>Example<BR>
for (i=0; i<10; i++) cout << i << endl;
<LI>Nested Loops<BR>
for (i=0; i<10; i++) <BR>
for (j=0; j<10; j++)<BR>
cout << i << "," << j <<endl;
</UL>
<H1>Switch Statement</H1>
<P>
Example<BR>
<CODE>switch (response) {<BR>
case 'q': exit(0); // quit<BR>
case 's': process_s(); break;<BR>
case 'h': process_h(); break;<BR>
default:<BR>
cout << "Invalid Response\n";<BR>
break;<BR>
}<BR>
</CODE>
<H1>Break/Continue</H1>
<UL>
<LI><TT>break</TT> exits the innermost loop
<LI><TT>continue</TT> begins the next iteration
</UL>
<P>
Example:<BR>
<CODE>for (i=0; i<n; i++) {<BR>
if (s[i] < 0) break; // exits loop<BR>
if (s[i] > 0) continue;<BR>
cout << "s[i]=0 for i=" << i;<BR>
}<BR>
cout << "i>=n or s[i]<0 for i=" <<
i;</CODE>
<H1>Topics</H1>
<UL>
<LI>Input/Output
</UL>
<H1>Input/Output</H1>
<UL>
<LI><CODE>#include <iostream.h></CODE>
<LI>Predefined streams:<BR>
<CODE>cin, cout, cerr, clog</CODE>
<LI>Examples:<BR>
<CODE>int x,y;<BR>
if (cin >> x >> y) {<BR>
cout << "Read: " << x << ","
<< y;<BR>
} else {<BR>
cerr << "Invalid Input!" << endl;<BR>
}</CODE>
</UL>
<H1>Errors in Input</H1>
<UL>
<LI><CODE>cin.eof()</CODE> Returns true on end of file
<LI><CODE>cin.fail()</CODE> Returns true on format error
<LI><CODE>cin.good()</CODE> Returns true if no error
<LI><CODE>cin.clear()</CODE> Clears an error
</UL>
<H1>Topics</H1>
<UL>
<!WA0><A HREF="http://www.cs.rpi.edu/~dugan/data_structures/mehta/lect2/sort">Source files for Example Program </A></UL>
<H1>Topics</H1>
<UL>
<LI>Conventions for C++ Programs/Projects
<LI>
</UL>
<H1>Main </H1>
<UL>
<LI>void main () { … }
<LI>int main () { … }
<LI>int main (int argc, char ** argv) { … }
</UL>
<P>
Example: main.cpp<BR>
<CODE>int main (int argc, char ** argv) {<BR>
for (int i=0; i<argc; i++) {<BR>
cout << "Argv[" << i << "]
= "<BR>
<< argv[i] << endl;<BR>
}</CODE>
<H1>Files</H1>
<UL>
<LI>Put declarations in Header (.h) Files<BR>
<CODE>iostream.h, Point.h</CODE>
<LI>Only header files should be included in other files (#include)
<LI>Put implementations in Source (.CC, .cpp, or .C) files<BR>
main.cpp, Point.cpp
<LI>Write Makefile to create executable
</UL>
<H1>Makefile Example</H1>
<UL>
<LI><CODE>CC = g++</CODE>
<LI>
<LI>main: main.o Point.o
<LI> $(CC) -o main main.o Point.o
<LI>Point.o: Point.h Point.cpp
<LI> $(CC) -c Point.cpp
<LI>main.o: Point.h main.cpp
<LI> $(CC) -c main.cpp
</UL>
<H1>Header Files</H1>
<UL>
<LI>Start header file (say Point.h) with:<BR>
<CODE>#ifndef _Point_h_<BR>
#define _Point_h_</CODE>
<LI>End each header file with:<BR>
#endif // _Point_h_
</UL>
<H1>Topics</H1>
<UL>
<LI>(Optional) Exercises
</UL>
<H1>Optional Exercises</H1>
<UL>
<LI>Create, Compile, and Link hello.cpp
<LI>Write Makefile for hello.cpp
</UL>
<P>
Write function rot13, to encrypt/decrypt a string. For example,
rot13("abxy") should return "nokl". Note:
use rot13.h, rot13.cpp
<UL>
<LI>Write a main program which rot13's the text in a file.
<LI>[W] Problem 1.6, 1.14, 1.15
</UL>
<P>
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