CH 3. INPUT/OUTPUT INSTRUCTIONS IN C

Question 1

c language uses __ in place of i/o instructions

Answer 1

functions

Question 2

there are some functions which have became standard for i/o these functions are stored in ___

Answer 2

standard i/o library ie header file

Question 3

before writing input output instructions every program must include ___

Answer 3

include

Question 4

state the use of #include in program

Answer 4

the statement will tell the compiler to search for the file, place its contents at the program. the contents of header will now be a part of program.

Question 5

state the types of i/o in c

Answer 5

console i/o
disk i/o
port i/o

Question 6

what is console i/o

Answer 6

the input is supplied from keyboard and output is printed on terminal

Question 7

what is disk i/o

Answer 7

i/o on floppy disks or hard disks ie secondary storage devices

Question 8

what is port i/o

Answer 8

i/o operations on ports

Question 9

the function used to input data is ___.

Answer 9

printf

Question 10

the function used to output data is __

Answer 10

scanf

Question 11

most of the standard i/o operations are included in ___ file.

Answer 11

stdio.h

Question 12

console i/o can be ___ and ___

Answer 12

formatted and unformatted

Question 13

___ i/o allows us to input/display output as per our requirements

Answer 13

formatted

Question 14

what is formatted i/o?

Answer 14

,

Question 15

Getch() are used to read characters in ____ input/output

Answer 15

Unformatted

Question 16

State the use of foll functions:

Getch()

Answer 16

Used in unformatted i/o. Used to read input from terminal without displaying it on screen

Question 17

State the use of following functions:

Getche

Answer 17

Will read the character typed with echoing(displaying) the enterer character on screen

Question 18

State the use of foll: getchar()

Answer 18

Used to read unformatted input and the entered characters will rchoe on screen when enter key is typed.

Question 19

State the use of foll: putch()

Answer 19

Outputs unformatted character on screen

Question 20

State the use of foll: putchar()

Answer 20

Used to print unformatted output when the variable is hardcored. The syntax is putchar(variable name)

Question 21

State syntax of foll:
Getchar
Putchar

Answer 21

1. Getchar: variable name=getchar();

Putchar: putchar=(variable name);

Question 22

Character functions are stored in headerfile ___.

Question 23

State the use of following functions in c:

Isalnum()

Answer 23

Checks whether the character is alphanumeric

Question 24

State the use of foll functions: isalpha()

Answer 24

To check whether the character is alphabet

Question 25

State the use of foll functions: isdigit()

Answer 25

Checks whether the character is digit

Question 26

State the use of foll functions: Islower()

Answer 26

Checks whether the character is lowercase

Question 27

State the use of foll functions: isprint()

Answer 27

Checks whether the character is printable

Question 28

State the use of foll functions: isspace()

Answer 28

Checks whether the character is whitespace

Question 29

Write the function for foll:

1. to check whether the character is punctuation mark
2. Is a whitespace character
3. Is printable character

Answer 29

1 ispunct()
2 isspace()
3 isprint()

Question 30

Write conversion specifier for the foll datatype:

1. Short unsigned int
2. Long signed int
3. Unsigned hexadecimal
4. Unsigned octal
5. Double real
6. Character unsigned
7. String

Answer 30

1. %u
2. %ld
3. %x
4. %o
5. %lf
6. %c
7. %s

Question 31

True/false: escape sequence are also included in format specifiers.

Answer 31

True

Question 32

Observe the program:
scanf(“%3d%2d”, &a&b);
Input: a=3221,b=20

State/explain the issue in this program.

Answer 32

Here, the width specified is less than the actual input. So, scanf will assign a=322,b=21 and will automatically stop post 1 and will not read b value. In order to avoid such situations one must either mention the accurate field width or just skip the field width.

Question 33

How much one write a program while reading multiple data items in scanf? What can be the error?

Answer 33

If the datatyoe doesnt match the dataitem scanf will skip reading further input. In order to avoid that…One must seperate the dataitems by spaces, newlines, tabs.

Question 34

Explain the foll: use of printf in formatted i/o

Answer 34

Use of field width.
If fw>input: leading blanks (right justified)
If input>fw: printed in full fw is overwritten (right justified)

Question 35

How does one prints output in c with:
Leading 0
Left justification
Right justification

Answer 35

O before fw
“-“ after %
Fw>value

Question 36

How can we print/read an float value in exponential form?

Answer 36

Syntax:
scanf(“%e”, &variable name);
printf(“%w.pe”,variable name);

Question 37

State and explain syntax of printf for float

Answer 37

printf(“w.pf”, variable name);

Explain w.pf

Question 38

%wc is used for ___ in scanf

Answer 38

Characters

Question 39

State the use of foll:
%[characters]
%[^characters]

Answer 39

1. Used by scanf for string.The characters entered in the [ ] are allowed in string. Used to read strings which have blank spaces
2. The characters inside the [ ] is not allowed in input string. Scanf will take values except them.

Question 40

State the conversion specifier in printf for character.

Answer 40

%wc

Question 41

State the conversion specifier in printf for string

Whats the use of precision?

Answer 41

%w.ps

P specifies first p values would be printed

Question 42

WRITE AND EXPLAIN THE PROGRAM FOR FOLL:

1. use of scanf for formatted int (with width specifier)

Answer 42

attemt ie write program with accurate output

Question 43

WRITE AND EXPLAIN THE PROGRAM FOR FOLL:

2. use of printf for printing value with left justification,right justification and leading with 0

Answer 43

attemt ie write program with accurate output

Question 44

WRITE AND EXPLAIN THE PROGRAM FOR FOLL:

3. scan and print formatted float in exponential form with leading 0, left and right justification.

Answer 44

attemt ie write program with accurate output

Question 45

WRITE AND EXPLAIN THE PROGRAM FOR FOLL:

4. to take character from user and print it in formats.

Answer 45

attemt ie write program with accurate output

Question 46

WRITE AND EXPLAIN THE PROGRAM FOR FOLL:

5. to take string from user and :
   a. read only lowercase letters.
   b. write the input in formats

Answer 46

attemt ie write program with accurate output

Question 47

WRITE AND EXPLAIN THE PROGRAM FOR FOLL:

6. take mixed values from user and print in formats

Answer 47

attemt ie write program with accurate output

Question 48

WRITE AND EXPLAIN THE PROGRAM FOR FOLL:

7. value of a=600, b=65.783, ch=’a’
   a. print a in jsutified form
   b. leading 0 with precision 4/exponent form
   c. with formats

Answer 48

attemt ie write program with accurate output

Question 49

true/false

scanf returns a int value.

Answer 49

true

Question 50

true/false

mixed datatypes can be input in any order using scanf

Answer 50

false

Question 51

true/false

printf can also print mixed datatypes

Answer 51

true

Question 52

true/false

unformatted i/o is not possible with printf

Answer 52

true

Question 53

true/false

the variable list has to match the format string in type while using printf

Answer 53

true