EE205 Data Structures for Engineers Lecture 1 Introduction

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EE205 Data Structures for EngineersLecture 1
Introduction
Feb 3, 2009 Kyu Ho Park (kpark_at_ee.kaist.ac.kr), h
ttp//core.kaist.ac.kr
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Syllabus

• Professor Kyu Ho Park
• 350-3425, kpark_at_ee.kaist.ac.kr
• TA YoungWoo Park, KiWoong Park, HyunCheol Seok,
  SungKyu Park
• ywpark, woongbak,hcseok,skpark_at_core.kaist.ac.kr
• References
• 1.Data Structures in C,Kalicharan,2008
• 2.Data Structures and Algorithm Analysis in C,
  2nd Ed.Weiss, 1997
• 3.Data Structures with Java, J.Hubbard and A.
  Huray2004,
• Web http//core.kaist.ac.kr

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Contents

• C Programming Overview
• Linked Structures
• Stacks
• Queues
• Hash Tables
• Recursion
• Trees
• Heap and Priority Queues
• Graphs
• Special Topics
• The lectures notes of the above issues are
  based on the reference1 and 3.

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Evaluation

• Homeworks 10
• Projects 35
• Quizzes etc. 5
• Midterm Exam 20
• Final Exam 30

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Review C -Programming

• Procedure to solve a problem in a computer
• Define the problem
• Analyze the problem
• Develop an algorithm for solving the problem
• Write the computer program which implements the
  algorithm
• Test and debug the program
• Document the program
• Maintain the program

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Define the problem

• I want to calculate the area of a circle

r
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Analyze the problem

• Confirm that we have clear understanding of it.
• Determine
• The inputs to the program
• The outputs of the program
• Problem Calculate area pr2
• Input the radius of the circle
• Output the area a of the circle
• I

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Algorithm to solve the problem

• Algorithm A well defined set of instructions to
  solve a problem
• AD 825 Abu Jafar Mohammed Musa al Khowarizmi
  wrote a book Kitab aljabr wal-mugabala

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Algorithm

• Computer instructions
• Input instructions
• Processing instructions
• Output instructions
• Data and variables
• When we give data to a program, that data is
  stored in memory.
• A program must be stored in the computers memory
  also.

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Data and variables

• r and area is called variable names, or simply
  variables.

Radius r
Area area
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Algorithm

• Ask for the radius of the circle
• Save the value in the box r
• Calculate the area of the circle
• Save the area in the box area
• Print the value in the box area
• Stop

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Write the program of the algorithm
Enter the value of your circle 10
Area of the circle314
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Program

• include ltstdio.hgt
• main()
• int r
• float area, pi3.14
• printf( Enter the value of the radius )
• scanf(d, r)
• area pirr
• printf(\nArea of a circle is f\n, area)

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Test and debug/Documentation

• Test and debug
• Compile the program
• Run the program
• Documentation
• Description of the problem
• The Algorithm for solving the problem
• The list of program
• Input test data and the output of the program

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Maintaining

• Error correction
• Modification of the program
• Migration to a new system

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scanf()

• Problem calculate 20 5
• Input
• Enter first number
• Enter second number
• Output
• 20 5

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Program

• include ltstdio.hgt
• main()
• int a,b,sum
• printf(Enter first input)
• scanf(d, a)
• printf(\nEnter second input)
• scanf(d, b)
• sum a b
• printf(\nd dd,a,b,sum)

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Reading strings gets() and strcp()

• char item20
• gets(item)// It reads characters and stores
  // them in item
• or
• strcpy(item, Data Structure)

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gets() and strcpy()

• include ltstdio.hgt
• include ltstring.hgt
• main()
• char item30, charStr30
• printf(Enter a string)
• gets(item)
• strcpy(charStr, EE205 Data Strcutures)
• printf(Strings item s and charStrs, item,
  charStr)

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Selection logic

• ! gt gt lt
• If(score gt50) printf(Pass\n)
• Else printf(Fail\n)
• True or False?
• (hgt1)(hlt99)
• hgt1hlt99
• ngt1 n lt12
• !(ngt1 nlt12)

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if

• A automobile repair shop charges W50,000 per hour
  for labor plus the cost of any replaced parts .
  But the minimum charge for the repair (including
  the cost of parts) is W100,000.
• or

Labor hour 3.5 Parts cost W20,000 Charge
for the repair
Labor hour 1.0 Parts cost W30,000 Charge for
the repair
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Algorithm

• Read the hours worked
• read the parts cost
• calculate (Labor charge Parts cost)
• If the total cost is less than W100,000,
• total charge 100,000
• 5. print the total charge

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if

• include ltstdio.hgt
• main()
• double hours, parts, repairCharge
• printf(Labor Hour?)
• scanf(lf, hours)
• printf(Parts Cost?)
• scanf(lf,parts)
• repairCharge hours50000 parts
• if( repairCharge lt 100000) repairCharge 100000
• printf(\nCharge for the repair W3.2f\n,
  repairCharge)

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If . else

• A student has got 5 examinations, each marked out
  of 100. The student will get S if his average
  mark is greater than or equal to 60, and F if
  his average mark is less than 60.
• or

Enter 5 marks Average is xxx , S
Enter 5 marks Average is xxx , F
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Algorithm

• Read 5 marks
• Calculate the average
• if the average is larger than 60,
• print S
• 4. else
• print F.

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Program

• include ltstdio.hgt
• main()
• int m1, m2,m3, m4, m5
• double average
• printf(Enter 5 marks)
• scanf(d d d d d,m1,m2,m3,m4,m5)
• average (m1m2m3m4m5)/5.
• printf(\nAverage is lf, average)
• if( average gt60.) printf(S\n)
• else
• printf(F\n)

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Data input from a filefscanf()

• FILE infopen(input.txt, r)
• int num
• fscanf(in, d,num)
• fclose(in)

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Program for File In

• // fileInOut.cpp Defines the entry point for
  the console application.
• //
• include "stdafx.h"
• include ltstdio.hgt
• int main(int argc, char argv)
• FILE infopen("input.txt", "r")
• int num, sum0,n0
• fscanf(in, "d", num)
• while(num!0)
• nn1
• sumsumnum
• fscanf(in,"d", num)

15.if(n0) printf("\nNo numbers
entered\n") 16.else 17. printf("\nd
numbers were entered\n") 18. printf("The
sum is d\n", sum) 19. printf("The
average is 3.2f\n",(double)sum/n) 20. 21.
fclose(in) 22. return 0 23.
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fprintf()

• To send output to the file, fprintf is used.
• FILE outfopen(output.txt, w)
• fprintf(out, The sum is d\n,sum)
• fclose(out)

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Program

• include "stdafx.h"
• include ltstdio.hgt
• int main(int argc, char argv)
• FILE infopen("input.txt","r")
• FILE outfopen("output.txt","w")
• int num, sum0, n0
• fscanf(in, "d", num)
• while(num !0)
• n n 1
• sumsum num
• fscanf(in,"d", num)

if( n0) fprintf(out, "No numbers enterd\n")
else fprintf(out, "d numbers were
entered\n",n) fprintf(out, "The sum
is d\n", sum) fprintf(out, "The
average is 3.2f\n", (double)sum/n)
fclose(in) fclose(out)
return 0
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for

• for i1 to 100 do
• sum sum 1
• end
• for(i1 ilt100 i)
• sum sum 1
• for( ltexpr1gtltexpr2gtltexpr3gt)
• ltstatementgt

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for and while

• for(ltexp1gt ltexp2gt ltexp3gt)
• ltstatementgt
• ltexp1gt
• while(ltexp2gt)
• ltstatementgt
• ltexp3gt

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Handling characters

• Character sets
• ASCII to represent characters
• Digits 0 9 codes 48 57
• Uppercase letters A Z codes 65 90
• Lowercase letters a z codes 97 to 122
• Control characters
• \n new line
• \f new page
• \t tab

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Character value

• printf(Char value c, Integer valued\n,a,
  a)
• Output Char value , Integer value
• Character variable
• char ch
• int n
• cha
• n a 5
• printf(Input character is c\n, ch)
• printf(Value n d\n, n)

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Read

• scanf(c, ch)
• or
• getchar()
• int c getchar()
• char ch getchar()//If getchar() is called when
  there is no more data, it returns -1 , which is
  the value of EOF defined in stdio.h.

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getchar()

• include ltstdio.hgt
• main()
• printf(Enter data and press Enter\n)
• char chgetchar()
• printf(The first char is c\n, ch)
• printf(Next code is c\n, getchar()

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getchar()

• include ltstdio.hgt
• main()
• printf( Input data and press Enter\n)
• for( int i1 ilt5, i)
• char ch getchar()
• printf(d th character is c\n, i, ch)

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Counting characters in a line

• include ltstdio.hgt
• main()
• char ch
• int countChar 0
• printf(Type and press Enter\n)
• while((chgetchar())!\n) countChar
• printf(No. of characters is d\n,countChar)

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Read/write characters from/to a filegetc() and
putc()

• 1. FILE in fopen(input.txt, r)
• 2. ch getc(in)//or fscanf(in, c, ch)
• FILE out fopen(output.txt, w)
• putc(ch, out) //or fprintf(out,c,ch)
• ? getchar() , putchar( )

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functions

• We have already used functions such as
  main(),printf(),scanf(), putc(), getchr(), etc.
• The use of functions avoid the need for repeated
  program codes.

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Calculating factorials

• f(n) nf(n-1)
• f(n-1)(n-1)f(n-2)
• f(2)2f(1)
• f(1)1f(0)
• f(0)1

Enter the value of n The value of n! is xxxx.
Algorithm 1. Get the value of n 2. Calculate
f(n) f(n)n(n-1)...1 3. Printout f(n)
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n!

• include ltstdio.hgt
• long int f(int n)
• main()
• int n
• printf(Enter the value n\n)
• scanf(d, n)
• printf(The value of d! is ld\n, n, f(n))

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f(n)

• long int f(int n)
• Int i
• long int p1
• If(ngt1)
• for(i2iltn i) p pi
• return p

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f(n) //recursion
Header of the function

• long int f(int n)
• if(n lt0) return 0
• else if(n 0) return 1
• else return nf(n-1)

Parameter list
Body of the function
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function

• How to give data to a function?
• int test(int n, char a, double b)

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nCr

• To calculate nCr
• Read n and r
• nCr n!/((n-r)! r!) //use the function f()
• Printout the result

Enter the value n and r of nCr The value of nCr
is XXXX
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Program for nCr

• include ltstdio.hgt
• long int f(int)
• long int combination(int, int)
• main()
• int n,r
• printf(Enter n and r of nCr\n)
• scanf(d d, n, r)
• printf(The value of dCd is ld, n, r,
  combination(n,r))

• long int combination(int n, int r)
• long int f(int)
• return f(n)/(f(n-r)f(r) )