sess-3

8/2/2019 Sess-3

1/48

NIIT SEM Q/CPR/CR/SESSION 3/1/VER06/95

REVIEW QUIZ

#1 Which of the following declarations are valid ?

a. int s_p_array [2][2] = {

{ 0, 0 },

{ 0, 0 }

};

main ()

{

..}

b. main (){

int s_p_array [2] [2] = {{ 0, 0 },

{ 0, 0 } }; }

8/2/2019 Sess-3

2/48


REVIEW QUIZ (contd.)

c. main ()

{

int s_p_array [2] [2];

}

# 2 Each element of a two-dimensional integer arrayhas to be initialized to 0. Which construct isuseful in initialising it ?

8/2/2019 Sess-3

3/48



#3 Some portions of the statement used to input thevalue of an element of a two-dimensional integerarray called s_p_array are missing. Fill in these

portions.

__________ ( ____, ___________ [2] [1]);

# 4 Consider the following # defines in a program :

# define SB 8# define PR 5

If the number of subjects (given by SB) were tochange to 6, what will the above statements

change to ?_____________

_____________

8/2/2019 Sess-3

4/48



# 5 Is the following declaration-cum-initializationvalid ?

Char limerick [ ] [ ] = {

I sat beside the duchess at tea,

It was just as I feared it would be,Her rumblings abdominal,

Where truly phenomenal,

And everyone thought it was me};

# 6 To print the second string in the above set, thestatements :

8/2/2019 Sess-3

5/48



# 7 Will the following statements suffice to convert acharacter to its upper-case equivalent and print itout?

ch=-32; /* ch is of type char */

printf(%c,ch);

# 8 In which of the following assignments is there apossibility of loss of data ? (I is an int, f a float

and d a double)

a. I = d;

b. d = f + I;

c. f = d + I;

8/2/2019 Sess-3

6/48



# 9 Write a statement using the ternary operator todivide two integers a and b and assign the resultto an integer variable quotient, ensuring

that division by zero does not take place.

# 10 State whether true or false.The statement :

total = total + 1;can be written as either :

total + = 1; or

total + + ;

8/2/2019 Sess-3

7/48



# 11 State whether true or false

In the snippet below :

if (y = 0)

{

statement x;

}

the statement x will always get executed.

8/2/2019 Sess-3

8/48


Solution To Review Quiz

# 1 a. Validb. Invalid, Initialization cannot be done at

the time of declaration within main ()

c. Valid

# 2 The for construct

# 3 scanf (%d, &s_p_array [2] [1]);

# 4 # define SB 6

# define PR 5

# 5 No. The second index (36 = length of second(longest) string + 1) has to be specified.

8/2/2019 Sess-3

9/48



# 6 printf (\n%s, limerick [1]); /* 1, NOT 2 */

# 7 No. one possible solution is :

ch = ( ( ch > = a) && (ch < = z) ) ? (ch - 32) :ch;printf (%c, ch);

# 8 a. Loss of data. Int set equal to a double.

b. No loss of data. Double on left-hand side.

c. Loss of data. All variables are convertedto double and the result (a double) is

truncated to a float.

8/2/2019 Sess-3

10/48



# 9 The statement is :

quotient = ( b ) ? ( a / b ) : LARGE_NO;

/* LARGE_NO has been # defined earlier */

# 10 True. Obviously, the second option :

total+ + ;

is more concise and thus commonly used.

# 11 False. Note that the if statement does not checkfor y equal to 0 but always sets y to 0. Thus the if

condition :(y = 0)

8/2/2019 Sess-3

11/48



is always false and statement x will never getexecuted. If the assignment to y was a non-zeronumber, the condition would be true and

statement x would get executed.

8/2/2019 Sess-3

12/48


SPL SESSIONObjectivesAt the end of this session, you will be able to :

Use the following operators in C programs :

Unary operators

Binary operators

Ternary operators

Compound assignment operators

Increment / decrement operators

Use character arithmetic and state the rules of

conversion between different data types

8/2/2019 Sess-3

13/48


SPL SESSION(contd.)

Objectives(contd.)

Use two-dimensional integer arrays in C programs in

terms of :

Declaration

Initialisation

Input to these arrays

Manipulation

Printing State the advantages of # define statements in the

preprocessor phase

8/2/2019 Sess-3

14/48


SPL SESSION(contd.)

Objectives (contd.) Use two-dimensional character arrays in C programs

in terms of :

Declaration

Initialisation

Printing

8/2/2019 Sess-3

15/48


OPERATORS IN C

Unary Operator The minus sign (-) changes the sign of a value

If j - 1 -j is equal to -1

If i = -3, -i is equal to 3

Binary Operators+, -, *, /, and %

The modulo operator % is used for finding theremainder in integer division

y = x % 5 /* x and y are both ints */

If x = 7, then y = 2

8/2/2019 Sess-3

16/48


OPERATORS IN C(contd.)

Character Arithmetic Character arithmetic is possible in C

char ch;

ch = S; /* ch set to S */

ch = ch + 32; /* ch now equal to sch= ch - 32; /* ch back to S */

8/2/2019 Sess-3

17/48



Type Conversions

Rules of conversion of mixed types in an assignment

d1 = f1 + i1;

/* d1 a double, f1 a float and i1 an int */ All operands of type char are converted to int

All floats are converted to doubles

If either operand is double, the other is converted

to a double, giving a double result

Loss of data could occur during the conversions dueto truncation f1 = 31 + i1; /* d1 a double, f1 a float and

i1 an int */

8/2/2019 Sess-3

18/48



Type Cast

Variables/values can be type cast to forcibly change

the result of an expression before making an

assignment

int i, j ;

double d;

d = (double) i/j;

8/2/2019 Sess-3

19/48



Ternary OperatorSyntax

test-expression ? T-expression : F-expression

Short (and sweet) substitute for the verboseif.else construct

Examplequotient = ( b ) ? ( a / b ) : LARGE_ NO;

8/2/2019 Sess-3

20/48



Compound Assignment Operators+ =, -=, *=, /= and %=

Used for writing shorter code without obscuring the

meaning

Examplesum + = this_ones_value;

is equivalent to :

sum = sum + this_ones_value;

8/2/2019 Sess-3

21/48



Increment/Decrement Operators+ + (Preincrement / Postincrement)

- - (Predecrement / Postdecrement)

For the commonly occurring situation on incrementing/ decrementing a variable by one

8/2/2019 Sess-3

22/48



Examplecounter+ + ;

- Note :

counter+ + ;

has the same effect as

+ + counter;

- However :

total = sum+ + ;

/* make total equal to sum */

/* and then increment sum */

8/2/2019 Sess-3

23/48



does not have the same effect as :

total = + + sum;

/* increment sum and then */

/* make total equal to sum */

TWO DIMENSIONAL INTEGER

8/2/2019 Sess-3

24/48


TWO-DIMENSIONAL INTEGER

ARRAYSDeclaration

int s_p_array [4] [4];

Declaration-cum-initialisationint s_p_array [4] [4] = {

{ 0, 0, 0, 0 },{ 0, 0, 0, 0 },

{ 0, 0, 0, 0 },

{ 0, 0, 0, 0 } };


8/2/2019 Sess-3

25/48



ARRAYS(contd.)

This sort of declaration-cum-initialization can be done

only outside main ()

A better way to initialize a two-dimensional array is to

use the for statement

Examplefor (s_counter = 0; 2_counter < 4 ;

s_counter+ + )

{

for ( p_counter = 0; p_counter < 4 ;

p_counter+ + ){s_p_array [s_counter] [p_counter] = 0; }

}


8/2/2019 Sess-3

26/48



ARRAYS(contd.)

Input The scanf () function is used

scanf (%d, &s_p_array [s_counter] [p_counter]);

Printing

The printf () function can be used

printf (\n%d, s_p_array [s_counter] [p_counter]); It is best to use the for statement during the input andthe printing process

THE PREPROCESSOR PHASE - #

8/2/2019 Sess-3

27/48


THE PREPROCESSOR PHASE - #

define

# define helps in writing more flexible programs# define SB 5

Before compilation all occurrences of SB will be

replaced by its value If the number of subjects ( SB ) were to change to

8, making the change in one place :

# define SB 8

will reflect the change across theprogram

TWO-DIMENSIONAL

8/2/2019 Sess-3

28/48


TWO DIMENSIONAL

CHARACTER ARRAYS

Declarationchar err_msg [5] [29];

Declaration-cum-Initialisation This sort of declaration can only be made outside

main()

char err_msg [5] [29] = {

Alls well,File not found,

No read permission for file,

Insufficient memory,No write permission for file,

};

8/2/2019 Sess-3

29/48


SPL SESSION(contd.)

The first index can be left out for a moreflexible declaration

The second index, however, has to bespecified

The second index must be at least one more

than the longest string

PrintingThe fourth error message can be printed using:

printf (\n%s,err_msg [3] );

8/2/2019 Sess-3

30/48


CLASSROOM EXERCISE

#1 An interesting word puzzle is the acrostic. Anextremely innovative acrostic is:

ROTAS

OPERA

TENET

AREPO

SATRO

8/2/2019 Sess-3

31/48


CLASSROOM EXERCISE(contd.)

Which in Lating meansArepo the sower hold

the wheels with force.

Observe that the acrostic is the samewhether read horizontally downward from leftto right, horizontally upwards from right to left,vertically downwards from left to right orvertically upwards from right to left.

Write a C program to read a 5x5 acrostic andcheck whether it reads the same in these

directions.

SOLUTION TO CLASSROOM

8/2/2019 Sess-3

32/48


EXERCISE

#include

char string [5] [6] ;

main()

{

int i, j, k,l;

char flag1=y, flag2=y;

/* Accept 5 string */

for (i=0 ; i

8/2/2019 Sess-3

33/48


EXERCISE(contd.)

scanf(%s, string[i]) ;

fflush(stdin) ;}

/*Elements are checked horizontally here*/for (i=0, j=0, k=4, I=4 ; i0 ; i++, k--){

for ( j=0, I=4 ; j0 ; j++, l--){

if (string[i][j] ==string[k][l]continue;

else{flag1=n;i=5;break;}

}}


8/2/2019 Sess-3

34/48


EXERCISE(contd.)

/*Elements are checked diagonally here */for (i=0, j=0,l=0,k=0; i

8/2/2019 Sess-3

35/48


EXERCISE(contd.)

if (flag1==n ll flag2==n){

printf (Not an acrostic\n);}

else{printf(Acrostic\n);

}}

CLASSROOM EXERCISE

8/2/2019 Sess-3

36/48


CLASSROOM EXERCISE

#2 Four cities are connected by routes asshown below :

The arrows between A and B indicate thatthere are flights from both A to B and B to A.Note that there is no direct flight between A andC, or B and D.

B

D

A

C

CLASSROOM EXERCISE

8/2/2019 Sess-3

37/48


CLASSROOM EXERCISE

Write a program to take in the origin anddestination of the flights along with theirdeparture and arrival times. (For simplicity,

assume that these times are rounded tohours and also that the arrival time is alwaysgreater than the departure time). Somesample data is provided below :

CLASSROOM EXERCISE

8/2/2019 Sess-3

38/48


CLASSROOM EXERCISE

From To Departure Time Arrival Time

A B 10:00 13:00B C 20:00 22:00C D 11:00 14:00D A 16:00 20:00A D 3:00 7:00D C 20:00 23:00

C B 8:00 10:00B A 12:00 15:00

After entering the data, modify the program sothat queries for durations of direct flightsbetween any two cities can be made throughthe program.


8/2/2019 Sess-3

39/48


EXERCISE

# 2# include

#define NO_OF_ROUTES 8#define UPPER_LOWER_DIFF 32

/*difference between ASCII*//*upper and lower case */

#define FIRST_PLACE A#define FIRST_PLACE_S

(FIRST_PLACE+ UPPER_LOWER_DIFF)

#define LAST_PLACE D#define LAST_PLACE_S

(LAST_PLACE + UPPER_LOWER_DIFF)


8/2/2019 Sess-3

40/48


EXERCISE(contd.)

main (){

char ch, from_place, to_place, origin[NO_OF_ROUTES],destin [NO_OF_ROUTES];

int counter, time, travel_time, o_d_diff,abs_o_d_diff, dep_time [NO_OF_ROUTES],arr_time [NO_OF_ROUTES];

for (counter= 0; counter < NO_OF_ROUTES;counter + + ){

do { /* Take in a valid origin */

printf (\nPlease input the ORIGIN : ) ;


EXERCISE( td )

8/2/2019 Sess-3

41/48


EXERCISE(contd.)

ch = getchar () ;fflush (stdin);

if ( ( ch> = FIRST_PLACE_S) & & (ch LAST_PLACE) );


EXERCISE( td )

8/2/2019 Sess-3

42/48


EXERCISE(contd.)

O.:gin [counter] = ch;printf (/n) ;

do /*Take in a valid destination */{

printf (\nPlease input the DESTINATION : ) ;

ch = getchar ();fflush (stdin);

if ( (ch> = FIRST_PLACE_S) && (ch< =LAST_PLACE_S) ){

ch- = UPPER_LOWER_DIFF;

}} while ( ( ch< FIRST_PLACE) | |(ch> LAST_PLACE) | | (ch = = origin

[counter] ) );


EXERCISE( td )

8/2/2019 Sess-3

43/48


EXERCISE(contd.)

destin [counter] = ch;printf (\n);

do /* Take in a valid departure time */

{

printf (\n Please input the DEPARTURE TIME : );

scanf(%d, & time) ;fflush (stdin) ;

} while ( ( time = 24) ) ;

dep_time [counter} = time;printf (\n) ;


EXERCISE( td )

8/2/2019 Sess-3

44/48


EXERCISE(contd.)

do /* Take in a valid arrival time */{

printf (\nPlease input the ARRIVAL TIME: );

scanf (%d, & time);fflush (stdin);

} while ( ( time < = deo_time [counter] ) | |

(time > = 24 ) );arr_time [counter] = time ;printf (\n);

} /* end of input */


EXERCISE(contd )

8/2/2019 Sess-3

45/48


EXERCISE(contd.)

do{

printf (\nYour trip is FROM : );

ch = getchar ();fflush (stdin);

if ( ( ch> = FIRST_PLACE_S) & & (ch LAST_PLACE) );


EXERCISE(contd )

8/2/2019 Sess-3

46/48


EXERCISE(contd.)

from_place = ch;printf (\n) ;

/*Take in passengers destination */do

{printf (\nYour trip is TO : );

ch = getchar ();fflush ( stdin) ;

if((ch>=FIRST_PLACE_S)&&(ch

8/2/2019 Sess-3

47/48


EXERCISE(contd.)

to_place=ch;printf(\n);

/* Determining and printing the duration of the flight */

o_d_diff=from_place-to_place;

abs_o_d_diff=(o_d_diff>0)?(o_d_diff):(-o_d_diff);

if(abs_o_d_diff==2)

{

printf(\n Sorry: No flights between the twoplaces);

}


EXERCISE(contd )

8/2/2019 Sess-3

48/48


EXERCISE(contd.)

else{

for(counter=0;(origin[counter]!=from_place)||(destin[counter]!=to_place); counter++)

travel_time=arr_time[counter]-dep_time[counter];

printf(\n Travel time between %c and %c is %dhours, from_place, to_place, travel_time);

}

printf(\n);

} /* end of main() */

sess-3

Documents