Input and Output

1
Input and Output
Knowledge Understand various types of input and
output syntaxes Skill Develop a program to
read/capture input and display output
2
Input and Output

• There are various functions available in C
  library that can be used for input and output
  activities. The two functions that will be
  explained here are printf() and scanf()
• printf() function is used for displaying
  characters on output devices (normally video
  display)
• scanf() function is used for reading/capturing
  characters from input devices (normally keyboard)

3
printf Function

• General format for printf function
• printf( output_format ,value_list )
• output_format tells function about the format
  that should be followed when displaying output
• value_list is a list of variables, constants,
  expressions or combination of them, which values
  are parts of the displayed output

4
printf Function

• Example
• printf(TK1913 C Programming\n\n)
• printf(List of Students\n)
• printf(Ahmad bin Ali)

TK1913 C Programming List of Students Ahmad bin
Ali _
TK1913 C Programming _
TK1913 C Programming List of Students _
5
printf Function

• printf() function can be used to display values
  of variable, constant and others
• To display a value, the format of the value has
  to be stated in the output_format. For example,
  the position of the value when the output is
  displayed

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printf Function

• Formats for displaying output values
• s for string
• c for character
• d for integer
• f for float/double
• e for float/double (scientific notation)

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printf Function - String
Format for string s

• Example
• printf( s , Display a string\n )
• Similar to
• printf( Display a string\n )

Normally, it is used to display an array of
characters
Example char name Nadiah printf( s ,
name )
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printf Function - String

• Example
• printf( Name s\nStudent No s, Ali Bakar,
  A92333)

Name Ali Bakar Student No A92333_
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printf Function - String

• Example
• printf( Name s\nStudent No s, Ali Bakar,
  A92333)

Name Ali Bakar Student No A92333_
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printf Function - Character
Format for character c
Example printf(c c c, U, K, M)
U K M_
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printf Function - Character
Example printf(ccc, U, K, M)
UKM_
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printf Function - Character
Example char1 U char2 K char3
M printf(c c c, char1, char2, char3)
U K M_
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printf Function - Integer

• Format for integer d
• General format
• ltmin_field_widthgt.ltmin_digitgtd

Example printf(Value is10.6d, 56342)
Value is 056342
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printf Function - Integer
Example printf(Value is10.3d, 56342)
Value is 56342
15
printf Function - Integer
Example printf(Value is10.4d, 56342)
Value is56342
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printf Function - Float

• Format for float f
• General format
• ltmin_field_widthgt.ltdecimal_placesgtf

Example printf(Value is10.4f, 32.6784728)
Value is 32.6784
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printf Function - Float
Example printf(Value is10f, 32.6784728)
Value is 32.678473
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printf Function - Float
Example printf(Value is10.5f, 32.6784)
Value is 32.67840
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printf Function - Float
Example printf(Value is5f, 32.6784728)
Value is32.678473
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printf Function - Float
Example printf(Value is.3f, 32.6784728)
Value is32.678
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printf Function - Float
Example include ltstdio.hgt void main( ) int
age float height age 21 height
1.73 printf(Ali is d years old and his height
is .5f meters\n, age, height)
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1.73
Ali is 21 years old and his height is 1.73000
meters _
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scanf Function

• General format for scanf function
• scanf( input_format , list_of_variables )
• input_format tells function about the format that
  should be followed when capturing data
• list_of_variables are locations in memory, in
  which the captured data is kept
• input_format should contain specification of each
  intended input data
• User needs to key-in data based on the format and
  specification set by the program

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scanf Function
Example printf(Key-in a character and a number
) scanf(cd, char, num) printf(Character
c\n, char) printf(Number d\n, num)
m
103
Key-in a character and a number m103
Key-in a character and a number m103 Character
m _
Key-in a character and a number m103 Character
m Number 103 _
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scanf Function
Example include ltstdio.hgt void main( ) int
day, month, year scanf(d d d, day,
month, year) printf(Day d, Month d,
Year d, day, month, year)
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12
2005
16 12 2005
16 12 2005 Day 16, Month 12, Year 2005_
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Conclusion Discussion

• Your Project
• Any problem during lab and tutorial sessions??

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End of Lecture 5