Computer Science Department FTSM Input and Output Knowledge: Understand various types of input and...
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Computer Science Department FTSMFTSM
Input and OutputInput and Output
Knowledge:Understand various types of input and output syntaxes
Skill:Develop a program to read/capture input and display output
TK1913-C ProgrammingTK1913-C Programming 22
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()printf() and scanf()scanf()
printf()printf() function is used for displaying characters on output devices (normally video display)
scanf() scanf() function is used for reading/capturing characters from input devices (normally keyboard)
Input and OutputInput and Output
TK1913-C ProgrammingTK1913-C Programming 33
printfprintf FunctionFunction General format for printfprintf function:
printf( output_format ,[value_list] );printf( output_format ,[value_list] );
output_formatoutput_format tells function about the format
that should be followed when displaying output
value_listvalue_list is a list of variables, constants,
expressions or combination of them, which
values are parts of the displayed output
TK1913-C ProgrammingTK1913-C Programming 44
printfprintf Function Function
Example:printf(“TK1913 C Programming\n\n”);printf(“List of Students\n”);printf(“Ahmad bin Ali”);
Example:printf(“TK1913 C Programming\n\n”);printf(“List of Students\n”);printf(“Ahmad bin Ali”);
TK1913 C Programming
_
TK1913 C Programming
List of Students
_
TK1913 C Programming
List of Students
Ahmad bin Ali _
What does What does \n\n mean?mean?
TK1913-C ProgrammingTK1913-C Programming 55
printfprintf Function Function printf()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_formatoutput_format. For example,
the position of the value when the output is
displayed
TK1913-C ProgrammingTK1913-C Programming 66
printfprintf Function Function
Formats for displaying output values: %s%s for stringstring %c%c for charactercharacter %d%d for integerinteger %f%f for floatfloat/doubledouble %e%e for floatfloat/double double (scientific notation)
TK1913-C ProgrammingTK1913-C Programming 77
printfprintf Function - String Function - StringFormat for string: %s%s
Example:
printf( “%s” , “Display a string\n” );
Similar to:
printf( “Display a string\n” );
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 );
Example:char name[ ] = “Nadiah”;
printf( “%s” , name );
Output format Value (a string constant)
Output format
Output format
Value (an array of characters)
TK1913-C ProgrammingTK1913-C Programming 88
printfprintf Function - String Function - String
Example:
printf( “Name: %s\nStudent No: %s”, “Ali Bakar”,
“A92333”);
Example:
printf( “Name: %s\nStudent No: %s”, “Ali Bakar”,
“A92333”);
Name: Ali Bakar
Student No: A92333_
Output format
TK1913-C ProgrammingTK1913-C Programming 99
printfprintf Function - String Function - String
Example:
printf( “Name: %s\nStudent No: %s”, “Ali Bakar”,
“A92333”);
Example:
printf( “Name: %s\nStudent No: %s”, “Ali Bakar”,
“A92333”);
Name: Ali Bakar
Student No: A92333_
TK1913-C ProgrammingTK1913-C Programming 1010
printfprintf Function - Character Function - CharacterFormat for character: %c%c
Example:printf(“%c %c %c”, ‘U’, ‘K’, ‘M’);
Example:printf(“%c %c %c”, ‘U’, ‘K’, ‘M’);
U K M_
TK1913-C ProgrammingTK1913-C Programming 1111
printfprintf Function - Character Function - Character
Example:printf(“%c%c%c”, ‘U’, ‘K’, ‘M’);
Example:printf(“%c%c%c”, ‘U’, ‘K’, ‘M’);
UKM_
TK1913-C ProgrammingTK1913-C Programming 1212
printfprintf Function - Character Function - CharacterExample:char1 = ‘U’;
char2 = ‘K’;
char3 = ‘M’;
printf(“%c %c %c”, char1, char2, char3);
Example:char1 = ‘U’;
char2 = ‘K’;
char3 = ‘M’;
printf(“%c %c %c”, char1, char2, char3);
U K M_
char1 U
char2 ?
char3 ?
char1 U
char2 K
char3 ?
char1 U
char2 K
char3 M
TK1913-C ProgrammingTK1913-C Programming 1313
printfprintf Function - Integer Function - Integer Format for integer: %d%d General format:
%[<min_field_width>.<min_digit>]d%[<min_field_width>.<min_digit>]d
Example:
printf(“Value is:%10.6d”, 56342);
Example:
printf(“Value is:%10.6d”, 56342);
Value is: 056342
10 characters
6 digits
TK1913-C ProgrammingTK1913-C Programming 1414
printfprintf Function - Integer Function - Integer
Example:
printf(“Value is:%10.3d”, 56342);
Example:
printf(“Value is:%10.3d”, 56342);
Value is: 56342
10 characters
5 digits
Min 3 digits
TK1913-C ProgrammingTK1913-C Programming 1515
printfprintf Function - Integer Function - Integer
Example:
printf(“Value is:%10.4d”, 56342);
Example:
printf(“Value is:%10.4d”, 56342);
Value is:56342
5 charactersMin 4 characters
TK1913-C ProgrammingTK1913-C Programming 1616
printfprintf Function - Float Function - Float Format for float: %f%f General format:
%[<min_field_width>.<decimal_places>]f%[<min_field_width>.<decimal_places>]f
Example:
printf(“Value is:%10.4f”, 32.6784728);
Example:
printf(“Value is:%10.4f”, 32.6784728);
Value is: 32.6784
10 characters
4 digits
TK1913-C ProgrammingTK1913-C Programming 1717
printfprintf Function - Float Function - Float
Example:
printf(“Value is:%10f”, 32.6784728);
Example:
printf(“Value is:%10f”, 32.6784728);
Value is: 32.678473
10 characters
6 digits (default)
TK1913-C ProgrammingTK1913-C Programming 1818
printfprintf Function - Float Function - Float
Example:
printf(“Value is:%10.5f”, 32.6784);
Example:
printf(“Value is:%10.5f”, 32.6784);
Value is: 32.67840
10 characters
5 digits
TK1913-C ProgrammingTK1913-C Programming 1919
Example:
printf(“Value is:%5f”, 32.6784728);
Example:
printf(“Value is:%5f”, 32.6784728);
Value is:32.678473
6 digits (default)
printfprintf Function - Float Function - Float
9 characters Min 5 characters
TK1913-C ProgrammingTK1913-C Programming 2020
Example:
printf(“Value is:%.3f”, 32.6784728);
Example:
printf(“Value is:%.3f”, 32.6784728);
Value is:32.678
3 digits
printfprintf Function - Float Function - Float
TK1913-C ProgrammingTK1913-C Programming 2121
printfprintf Function - Float Function - FloatExample:#include <stdio.h>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);}
Example:#include <stdio.h>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);}
Ali is 21 years old and his height is 1.73000 meters
_
age ?
height ?
21
1.73
TK1913-C ProgrammingTK1913-C Programming 2222
scanfscanf Function Function General format for scanfscanf function:
scanf( input_format , list_of_variables );scanf( input_format , list_of_variables ); input_format input_format tells function about the format that should be
followed when capturing data list_of_variableslist_of_variables are locations in memory, in which the
captured data is kept input_formatinput_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
TK1913-C ProgrammingTK1913-C Programming 2323
scanfscanf Function FunctionExample:
printf(“Key-in a character and a number: “);
scanf(“%c%d”, &char, &num);
printf(“Character: %c\n”, char);
printf(“Number: %d\n”, num);
Example:
printf(“Key-in a character and a number: “);
scanf(“%c%d”, &char, &num);
printf(“Character: %c\n”, char);
printf(“Number: %d\n”, num);
Key-in a character and a number:
char ?
num ?
m
Key-in a character and a number: m103
103
Key-in a character and a number: m103
Character: m
_
Key-in a character and a number: m103
Character: m
Number: 103
_
TK1913-C ProgrammingTK1913-C Programming 2424
scanfscanf Function FunctionExample:#include <stdio.h>
void main( ) {int day, month, year;scanf(“%d %d %d”, &day, &month, &year);printf(“Day: %d, Month: %d, Year: %d”, day, month, year);}
Example:#include <stdio.h>
void main( ) {int day, month, year;scanf(“%d %d %d”, &day, &month, &year);printf(“Day: %d, Month: %d, Year: %d”, day, month, year);}
16 12 2005
month ?
year ?
day ?16
12
2005
16 12 2005
Day: 16, Month: 12, Year: 2005_
TK1913-C ProgrammingTK1913-C Programming 2525
Conclusion & DiscussionConclusion & Discussion Your Project Any problem during lab and tutorial
sessions??
TK1913-C ProgrammingTK1913-C Programming 2626
End of Lecture 5End of Lecture 5
Yes !! That’s all? Yes !! That’s all? What’s next???What’s next???
OPERATORS & OPERATORS & EXPRESSIONSEXPRESSIONS on the way on the way … …