17 October 2014

IO Functions - printf and scanf

Printf() is a function to print strings to the display unit and
scanf() is to scan the input through the keyboard
the f in the printf and scanf are called as format. That is, printf() and scanf() will print and scan in some particular format, it is the duty of the developer to provide that formats.
For example
printf(“a=%d, b=%d”, a,b); //This function will print a=10, b=20 if the values of a and b are 10 and 20
scanf(“%f”, &a); //this will accept a float number as the specifier is %f which is for float, See the Ampersand symbol which to tell the compiler to store the variable into the address.
Here is the list of format codes or format specifiers
scanf() format codes
Code Meaning
%c read a single character
%d read a decimal integer
%f read a floating point value
%e read a floating point value (even in exponential format)
%g read a floating point value
%h read a decimal, heaxadecimal or octal integer
%o read an octal integer
%s read a string
%u read an unsigned integer
%x read a hexadecimal integer
h for short integers like %hd
l for long integers like "%ld
L for long double like %Lf
printf() format codes
Code Meaning
%c prints a single character
%d print a decimal integer
%e print a floating point value in exponential form
%f print a float point value
%g print a float point value either in f type or e type depending on the value
%i print a signed decimal integer
%o prints an octal integer
%s prints a string
%u print an unsigned integer
%x print a hexadecimal number

Backslash Character constants or Escape Characters
There are some characters inside the double quotes for printf() and scanf() which are escaped by the compiler and hence it will the next character after the escape characters
Character What it will do
\n go to the new line
\t horizontal tab
\a alert bell
\f form feed
\r carriage return
\” will print “
\’ will print ‘
\? will print ?
\\ will print \
\v vertical tab
\b backspace

 T S Pradeep Kumar