Computer Science Department FTSM Input and Output Knowledge: Understand various types of input and output syntaxes Skill: Develop a program to read/capture input and display output

TK1913-C Programming2 TK1913-C Programming 2 printf()scanf() 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() 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 Output

TK1913-C Programming3 TK1913-C Programming 3 printf Function printf General format for printf function: printf( output_format,[value_list] ); output_format output_format tells function about the format that should be followed when displaying output value_list value_list is a list of variables, constants, expressions or combination of them, which values are parts of the displayed output

TK1913-C Programming4 TK1913-C Programming 4 printf 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 \n mean?

TK1913-C Programming5 TK1913-C Programming 5 printf Function printf() printf() function can be used to display values of variable, constant and others output_format 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

TK1913-C Programming6 TK1913-C Programming 6 printf Function Formats for displaying output values: %sstring %s for string %ccharacter %c for character %dinteger %d for integer %ffloatdouble %f for float/double %efloatdouble %e for float/double (scientific notation)

TK1913-C Programming7 TK1913-C Programming 7 printf Function - String %s Format for string: %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 formatValue (a string constant)Output format Value (an array of characters)

TK1913-C Programming8 TK1913-C Programming 8 printf 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 Programming9 TK1913-C Programming 9 printf 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 Programming10 TK1913-C Programming 10 printf Function - Character %c Format for character: %c Example: printf(“%c %c %c”, ‘U’, ‘K’, ‘M’); Example: printf(“%c %c %c”, ‘U’, ‘K’, ‘M’); U K M_

TK1913-C Programming11 TK1913-C Programming 11 printf Function - Character Example: printf(“%c%c%c”, ‘U’, ‘K’, ‘M’); Example: printf(“%c%c%c”, ‘U’, ‘K’, ‘M’); UKM_

TK1913-C Programming12 TK1913-C Programming 12 printf Function - Character Example: 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 Programming13 TK1913-C Programming 13 printf Function - Integer %d Format for integer: %d General format:%[<min_field_width>.<min_digit>]d Example: printf(“Value is:%10.6d”, 56342); Example: printf(“Value is:%10.6d”, 56342); Value is: characters 6 digits

TK1913-C Programming14 TK1913-C Programming 14 printf Function - Integer Example : printf(“Value is:%10.3d”, 56342); Example : printf(“Value is:%10.3d”, 56342); Value is: characters 5 digits Min 3 digits

TK1913-C Programming15 TK1913-C Programming 15 printf Function - Integer Example : printf(“Value is:%10.4d”, 56342); Example : printf(“Value is:%10.4d”, 56342); Value is: characters Min 4 characters

TK1913-C Programming16 TK1913-C Programming 16 printf Function - Float %f Format for float: %f General format:%[<min_field_width>.<decimal_places>]f Example: printf(“Value is:%10.4f”, ); Example: printf(“Value is:%10.4f”, ); Value is: characters 4 digits

TK1913-C Programming17 TK1913-C Programming 17 printf Function - Float Example: printf(“Value is:%10f”, ); Example: printf(“Value is:%10f”, ); Value is: characters 6 digits (default)

TK1913-C Programming18 TK1913-C Programming 18 printf Function - Float Example: printf(“Value is:%10.5f”, ); Example: printf(“Value is:%10.5f”, ); Value is: characters 5 digits

TK1913-C Programming19 TK1913-C Programming 19 Example: printf(“Value is:%5f”, ); Example: printf(“Value is:%5f”, ); Value is: digits (default) printf Function - Float 9 characters Min 5 characters

TK1913-C Programming20 TK1913-C Programming 20 Example: printf(“Value is:%.3f”, ); Example: printf(“Value is:%.3f”, ); Value is: digits printf Function - Float

TK1913-C Programming21 TK1913-C Programming 21 printf Function - Float Example: #include 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 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 meters _ age ? height ?

TK1913-C Programming22 TK1913-C Programming 22 scanf Function scanf General format for scanf function: scanf( input_format, list_of_variables ); input_format input_format tells function about the format that should be followed when capturing data list_of_variables list_of_variables are locations in memory, in which the captured data is kept input_format 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

TK1913-C Programming23 TK1913-C Programming 23 scanf Function Example: 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: m Key-in a character and a number: m103 Character: m _ Key-in a character and a number: m103 Character: m Number: 103 _

TK1913-C Programming24 TK1913-C Programming 24 scanf Function Example: #include 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 void main( ) { int day, month, year; scanf(“%d %d %d”, &day, &month, &year); printf(“Day: %d, Month: %d, Year: %d”, day, month, year); } month ? year ? day ? Day: 16, Month: 12, Year: 2005_

TK1913-C Programming25 TK1913-C Programming 25 Conclusion & Discussion Your Project Any problem during lab and tutorial sessions??

TK1913-C Programming26 TK1913-C Programming 26 End of Lecture 5 Yes !! That’s all? What’s next??? OPERATORS & EXPRESSIONS on the way …