Contents

Syntax

printf("ControlString", arg1, …, argN);

Key Points

Prints ControlString to Standard Output (the terminal on a PC, typically a Universal Asynchronous Receiver Transmitter (UART) on microcontrollers)
The MPLAB^® X IDE Simulator uses the UART1 Output window to display text written to the UART using printf()
All comma-separated parameters are optional except for ControlString
The argument parameters (arg1, …, argN above) can be variables or other data to be embedded within ControlString
Placeholders are put in ControlString to indicate where the value of an argument parameter should be inserted
Placeholders indicate the position in string and format to be used in printing data embedded within ControlString
printf() requires a huge amount of memory. Best used for debugging only unless you need all of its functionality

1    {
2          int a = 5;
3          int b = 10;
4          printf("a = %d\nb = %d\n", a, b);
5    }

printf2

The code above would produce the following output:

a = 5
b = 10
_

Where "_" indicates the position of the cursor at the end of the operation.

The code in Example 1 defines two variables: a and b
We want to print their values as part of a string that indicates which value goes with which variable
The ControlString is "a = %d\nb = %d\n"
Each %d is a placeholder that indicates where one of the arguments should be inserted and how it should be formatted when printed
The value of a is inserted at the position of the first %d and the value of b is inserted at the position of the second %d
The d in the %d is called a format specifier or a conversion character and indicates that the value should be printed as a signed decimal integer
The \n is an escape sequence indicating that a new line should be inserted, causing the cursor to go down to the next line before continuing to print

Format Specifier	Meaning
%c	Single character
%s	String (all characters until '\0')
%d	Signed decimal integer
%o	Unsigned octal integer
%u	Unsigned decimal integer
%x	Unsigned hexadecimal integer with lower case digits (e.g. 1a5e)
%X	Same as %x but with upper case digits (e.g. 1A5E)
%f	Signed decimal value (floating point)
%e	Signed decimal value with exponent (e.g. 1.26e-5)
%E	Same as %e but uses upper case E for exponent (e.g. 1.26E-5)
%g	Same as %e or %f, depending on size and precision of value
%G	Same as %g but will use capital E for exponent