2. Cs288 Intensive Programming in Linux
Instructor: C F Yurkoski
Section web site:
Class 6
6-9-15

3. Topics today Test revu Final schedule Project Revu
Some last notes on bash
Intro to C.
Time for questions

4. Test Revu Written Revu Problem 12 Problem 13
Moodle would not let me assign grades over 100.

5. Average grade:

9. everyone
Ø (nothing)

10. true x

11. two 3

12. Problem12, average grade: 71%
grep -v "^hourly status" | grep "^hourly" | cut -f2,4 | while read data do
temp=($data)
hours=${temp[$count-1]}
let pay=${hours}*${1}
x=0
let namesize=$count-1
while [ $x -lt $namesize ]
echo -n "${temp[$x]} "
let x=x+1
done
echo -e \\t\$$pay

13. Extra credit
afsconnect1-111 test1 >: diff makechecks extracredit 15c15 < done --- > done | sort afsconnect1-112 test1 >:

14. Prob13 average grade 57%
>: ./getmany_twits "Ernst" "Luther Strange" "Trump"
Ernst @SenJoniErnst
Luther Strange @SenatorStrange
no twitter handle found for Trump
>:

15. if [ $# != 1 ] then echo "Usage: $0 name" >&2 exit 1 fi twit=`wget -q -O - | grep | grep "$1" | cut -f2 | cut -d"<" -f1` if [ "$twit" != "" ] echo else echo no twitter handle found for $1 >&2 exit 0

16. Use \ to make long lines more readable
while [ $# -gt 0 ] do twit=`wget -q -O - senate/members?lang=en | grep | grep "$1" | cut -f2 | cut -d"<" -f1` if [ "$twit" != "" ] then echo -e $1\\t else echo no twitter handle found for $1 fi shift done

17. Final schedule
The schedule can be downloaded at this link: 5/11/ :00 PM-8:30 PM GITC 1400

18. Project revu

19. cfy

21. cfy

22. cfy

23. cfy

24. Some final notes on bash
IFS
mkdir mv cp rm
tail
touch
find
man
source

26. Some Basics of C
Created by Dennis Ritchie of Bell Labs in the early 70s.
6-9-15

27. text
cfy

28. Tokens in C Keywords Identifiers Constants Strings Symbols Operators
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29. Character Set
Letters
Digits
Special characters
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30. Identifiers Start with underscore or a letter
Can contain letter, underscore and numbers
Case sensitive
Cannot be a keyword
No longer limited in length
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31. C keywords auto break case char const continue default
do double else enum extern float
for goto if int long register return
short signed sizeof static struct
typedef union unsigned void volatile while
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32. Some Basic Types
char int float short long double
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33. Data types char int float 6-9-15 signed char unsigned char short
short int
signed short
signed short int
unsigned short 
unsigned short int
int
signed
signed  int
unsigned
unsigned int
long
long int
signed long
unsigned long
unsigned long int
long long …
float
6-9-15

34. Contants Integer range -32768 to +32767
Real expressed as mantissaeexponent e.g.: 12.3e4 range -3.4e38 to 3.4e38
char constants are ascii characters
String contants- series of characters terminated by a null character.
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35. Instructions
Declaration
I/O
Arithmetic
Control
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36. Operators Arithmetic Relational Logical Bit-wise Assignment
Conditional
Increment and decrement
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37. Arithmetic Operators + = * / %
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38. Relational Operator
>
>=
<
<= == !=
cfy

39. Logical Operators
&& || !
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40. Bitwise Operators* (complement, or, and, xor and shift)~ |
& ^
>>
<< *these cannot be used with floats
cfy

41. Increment & decrement ++ --
cfy

42. Assignment Operators = += -= *= %= /=
cfy

43. Conditional Operator ? : exp1 ? exp2 : exp3
If exp1 is non-zero value of expression is exp2 otherwise it is exp ? 2 : 3
cfy

44. Operator Precedence left to right
* / %
+ -
cfy

45. Some Basics
/* Comments */ { blocks } Parameters ( ) # preprocessor directive Statements end with ; Loops: for while Conditionals if then
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46. First program
/* This is a comment */ #include <stdio.h> /* preproc d*/ main() { printf("hello world\n"); }
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47. Basic printf formats %i or %d int %c char %f float %s string
cfy

48. Width and precision %d print as decimal integer
at least 6 characters wide
%f print as floating point
%6f print as floating point, at least 6
characters wide
%.2f print as floating point, 2 characters after
decimal point
cfy

49. I/O
C=getchar();
putchar(C);
cfy

50. for statement
for(init;condition;increment) { statement(s); } for(i=0;i<5;i++) printf(“%d\n”,i);
cfy

51. Symbolic Contants #define name replacement text #define LIMIT 30
cfy

52. Escape sequences \a 07 Alarm (Beep, Bell) \b 08 Backspace
\f 0C Formfeed
\n 0A Newline (Line Feed)
\r 0D Carriage Return
\t 09 Horizontal Tab
\v 0B Vertical Tab
\\ 5C Backslash
\‘ 27 Single quotation mark
\“ 22 Double quotation mark
\? 3F Question mark
\nnn any The character whose numerical value is given by nnn interpreted as an octal number
\xhh any The character whose numerical value is given by hh interpreted as a hexadecimal number
6-9-15

53. if statement
if ( expression) statement else if ( expression ) else if ( expression )
cfy

54. arrays
int myarray[10];
cfy

55. functions
int function ( int param1, char param2); … int function ( int param1, char param2) { int local1, local2; /* call by value */ retval=function2 (local1); return(10); }
cfy

56. argv, argc
#include <stdio.h> int main (int argc, char *argv[]) { printf(“%s\n”,argv[0]); return 0; }
cfy

57. compiler
cc file.c –o file
cfy

58. More basic C More on arrays:
Array initialization during declaration: int num[5];
num[0]=1;
int num[5]={1,2,3,4,5};
cfy

59. Multi-dimensional arrays
int a[2][3]; int a[2][3]={{1,2,3},{4,5,6}};
cfy

60. Multi-dimensional arrays cont
#include <stdio.h> main() { int a[2][3]={{1,2,3},{4,5,6}}; int i,j; for(i=0;i<2;i++) for(j=0;j<3;j++) printf("a[%d][%d]=%d\n",i,j,a[i][j]); }
cfy

61. Multi-dimensional arrays cont
afsconnect1-58 >: ./a.out a[0][0]=1 a[0][1]=2 a[0][2]=3 a[1][0]=4 a[1][1]=5 a[1][2]=6
cfy

62. Strings are just arrays of characters.
#include <stdio.h> main() { char name1[25]="NJIT"; char name2[25]={'N','J','I','T','\0'}; printf("name1=%s\n",name1); printf("name2=%s\n",name2); } >: ./a.out name1=NJIT name2=NJIT
cfy

63. Strings (cont).
main() { char name1[25]="NJIT"; char name2[25]={'N','J','I','T','\0'}; char *name3="NJIT"; printf("name1=%s\n",name1); printf("name2=%s\n",name2); printf("name3=%s\n",name3); } afsconnect1-67 public_html >: ./a.out name1=NJIT name2=NJIT name3=NJIT
cfy

64. Strings (cont).
Header file string.h Some examples: strcmp String Compare strcat String Concatenation memcpy Copy Memory Block strlen String Length
cfy

65. General form: Strcat(string1,string2) Appends string2 to string1;
Strings (cont).
General form: Strcat(string1,string2) Appends string2 to string1;
cfy

66. Addresses! & used to get the address of a variable main() { int i=666;
printf("i= %d\n",i);
printf("&i= %d\n",&i); }
afsconnect1-72 public_html >: ./a.out
i= 666
&i=
cfy

67. More C keywords
switch break, continue, goto sizeof Storage classes: auto register extern static
cfy

68. switch( Grade ) { case 'A' : printf( "Excellent\n" ); case 'B' : printf( "Good\n" ); case 'C' : printf( "OK\n" ); case 'D' : printf( "Mmmmm....\n" ); case 'F' : printf( "You must do better than this\n" ); default : printf( "What is your grade anyway?\n" ); }
cfy

69. label: while (true) { if(a) break; if(b) continue; if(c) goto label; }
cfy

70. printf("sizeof i= %d\n",sizeof(i)); printf("sizeof array= %d\n",
main() {
int i=666;
char array[15];
double n;
printf("sizeof i= %d\n",sizeof(i));
printf("sizeof array= %d\n",
sizeof(array));
printf("sizeof n= %d\n", sizeof(n)); }
>: ./a.out
sizeof i= 4
sizeof array= 15
sizeof n= 8
cfy

71. static Has number of implications:
Local static variables initialized only once and retain their value.
Guaranteed to be automatically initialized to zero if not otherwise initialized.
Global static variable inaccessible outside the file.
Can be applied to functions.
cfy

72. Structures!
struct <name> { element1; element2; … }
cfy

73. Structures example
struct class { char name[30]; int number; char instructor[25]; int students[35]; };
cfy

74. Structures element dereferencing
structure-variable.stucture-member; e.g.: x=class.number;
cfy

75. Arrays of Structures
struct class semester[30]; struct grades { char name[30]; int id; int grades[10]; }g[35];
cfy

76. Unions
struct class semester[30]; union students { long x; char grades[8]; }g[35];
cfy

77. sizeof can be applied to unions and structures
Structures can be nested.
cfy

78. Pointers
General form: datatype *ptrname; int x=666, y=555; Int *p; p = &x; y = *p;
cfy

79. Homework Write a hello world program – do today in class
Do problem 1-4 from text
Write a program which reads stdin and converts any local case characters to upper case.
Redo problem 4 from class 2 as a C program.
Do problem 1-8 from text
cfy

80. problem 4
Write a C program, sort.c, which sorts a list of command line parameters in ascending order. For example, your command will look something like:  $ sort and type enter. Your program will return:
cfy

81. Homework cont. Do exercise 1-19 from the text.
cfy