scanf function can be used to input a string containing more than one character from the keyboard. The field specification for reading a string containing sequence of character is:

%ws   or   %wc

The corresponding argument should be a pointer to a character array. However, %c may be used to read a single character when the argument is a pointer to a char variable.

Unlike gets (), which reds a string until RETURN is typed, scanf () reads a string until the first white space character (RETURN, TAB or space) is encountered. For example:

char str [20];
scanf (“%s”, str);

The %n specifier

The %n specifier instructs scanf () to assign the number of characters read at the point at which the %n was encountered to the variable pointed to by corresponding argument.

Program – Illustration of %n

#include <stdio.h>
void main ()
{
     char name [20];
     scanf (“%6s”, name);
     printf (“%8s”, name);
}

Output

Bhubaneswar
Bhuban

Using a Scanset

A scanset defines a set of characters which may be read and assigned to the corresponding character array.

A scanset is defined by placing the characters inside square brackets prefixed with a %, as in the following example:

% [“XYZ”]

Scanf () will then continue to read characters and continue to put them into the array until it encounters a character not in the scanset. For example, given the following code:

scanf (%d%[abcdefg]%s”, &I, str, str2);
printf (“%d %s %s”, i, str, str2);

entering 123abcdtye followed by ENTER would display:

123 abcd tye

because the t is not part of the scanset, causing it and the remaining characters to be put into str2.

If the first character in the set is a ^, scanf () will accept any character not defined by the scanset. A range may be specified using a hyphen. Scansets are case sensitive.

Program – Illustration of scanset

#include<stdio.h>
void main ()
{
   int i;
   char str [20], str2[20];
   scanf (“%d %[abcdefh] %s”, &i, str, str2);
   printf (“&d\n%s\n%s\n”, i, str, str2);
}

Output

123abcdtye
123
abcd
tye

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