scanf Function

Scans formatted text from stdin.

Include

<stdio.h>

Prototype

int scanf(const char *format, ...);

Arguments

format: format control string
...: optional arguments

Return Value

Returns the number of items successfully converted and assigned. If no items are assigned, a 0 is returned. EOF is returned if an input failure is encountered before the first.

Remarks

Each format specifier begins with a percent sign followed by optional fields and a required type as shown here:

%[*][width][modifier]type

*

Indicates assignment suppression. This will cause the input field to be skipped and no assignment made.

width

Specify the maximum number of input characters to match for the conversion, not including white space that can be skipped.

modifier

h modifier	Used with type d, i, o, u, x, X; converts the value to a `short int` or `unsigned short int`.
h modifier	Used with n; specifies that the pointer points to a `short int`.
l modifier	Used with type d, i, o, u, x, X; converts the value to a `long int` or `unsigned long int`.
l modifier	Used with n; specifies that the pointer points to a `long int`.
l modifier	Used with c; specifies a wide character.
l modifier	Used with type e, E, f, F, g, G; converts the value to a `double`.
ll modifier	Used with type d, i, o, u, x, X; converts the value to a `long long int` or `unsigned long long int`.
ll modifier	Used with n; specifies that the pointer points to a `long long int`.
L modifier	Used with e, E, f, g, G; converts the value to a `long double`.

type

d, i	`signed int`.
o	`unsigned int` in octal.
u	`unsigned int` in decimal.
x	`unsigned int` in lowercase hexadecimal.
X	`unsigned int` in uppercase hexadecimal.
e, E	`double` in scientific notation.
f	`double` decimal notation.
g, G	`double` (takes the form of e, E or f as appropriate).
c	`char` - a single character.
s	`string`.
p	value of a pointer.
n	The associated argument shall be an integer pointer into which is placed the number of characters written so far. No characters are printed.
%	A `%` character is printed.

Example

For MPLAB X Simulator:

#include <stdio.h>
 #include <libpic30.h>

int main(void)
{
  int number, items;
  char letter;
  char color[30], string[30];
  float salary;

  __attach_input_file("UartIn.txt");
  printf("Enter your favorite number, "
         "favorite letter, ");
  printf("favorite color desired salary "
         "and SSN:\n");
  items = scanf("%d %c %[A-Za-z] %f %s", &number,
  &letter, &color, &salary, &string);

  printf("Number of items scanned = %d\n", items);
  printf("Favorite number = %d, ", number);
  printf("Favorite letter = %c\n", letter);
  printf("Favorite color = %s, ", color);
  printf("Desired salary = $%.2f\n", salary);
  printf("Social Security Number = %s, ", string);
}
// If not using the simulator, remove these lines:
// #include <libpic30.h>
// __attach_input_file("uart_in.txt");

Example Input

Contents of UartIn.txt (used as stdin input for simulator):

5 T Green 300000 123-45-6789

Example Output

Enter your favorite number, favorite letter, 
favorite color, desired salary and SSN:
Number of items scanned = 5
Favorite number = 5, Favorite letter = T
Favorite color = Green, Desired salary = $300000.00
Social Security Number = 123-45-6789