Non-printable ASCII characters list

This blog post explains the non printable characters with their ASCII (American Standard Code for Information Interchange) value in decimal and hex format. The non-printing characters are characters for content designing in word processors, which are not displayed at printing.

Table of non-printable ASCII characters:

The following table contains the non-printable characters with their ASCII value in decimal and hex format.

Non Printable Characters
DEC	HEX	CHARACTER (CODE)	DEC	HEX	CHARACTER (CODE)
0	0	NULL	16	10	DATA LINK ESCAPE (DLE)
1	1	START OF HEADING (SOH)	17	11	DEVICE CONTROL 1 (DC1)
2	2	START OF TEXT (STX)	18	12	DEVICE CONTROL 2 (DC2)
3	3	END OF TEXT (ETX)	19	13	DEVICE CONTROL 3 (DC3)
4	4	END OF TRANSMISSION (EOT)	20	14	DEVICE CONTROL 4 (DC4)
5	5	END OF QUERY (ENQ)	21	15	NEGATIVE ACKNOWLEDGEMENT (NAK)
6	6	ACKNOWLEDGE (ACK)	22	16	SYNCHRONIZE (SYN)
7	7	BEEP (BEL)	23	17	END OF TRANSMISSION BLOCK (ETB)
8	8	BACKSPACE (BS)	24	18	CANCEL (CAN)
9	9	HORIZONTAL TAB (HT)	25	19	END OF MEDIUM (EM)
10	A	LINE FEED (LF)	26	1A	SUBSTITUTE (SUB)
11	B	VERTICAL TAB (VT)	27	1B	ESCAPE (ESC)
12	C	FF (FORM FEED)	28	1C	FILE SEPARATOR (FS) RIGHT ARROW
13	D	CR (CARRIAGE RETURN)	29	1D	GROUP SEPARATOR (GS) LEFT ARROW
14	E	SO (SHIFT OUT)	30	1E	RECORD SEPARATOR (RS) UP ARROW
15	F	SI (SHIFT IN)	31	1F	UNIT SEPARATOR (US) DOWN ARROW

Now let’s see a C program to validate the above-mentioned non-printable characters.

Now you are thinking about how I will validate?

The answer to your question is that I will use the isprint function for each character. The isprint is a library function that returns a non-zero value if the argument is a printable character.

In the following code, I am creating an array of ASCII code for non-printing characters and validating each character through the isprint library function in a “for loop“.

#include <stdio.h>
#include <ctype.h>

int main()
{
    int i = 0;

    //ASCII value of all non-printable character
    int asciiValue[] =
    {
        0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,
        17,18,19,20,21,22,23,24,25,26,27,28,29,30,31
    };

    //Get array size
    const int arraySize = sizeof(asciiValue)/sizeof(asciiValue[0]);

    // looping through all elements of array
    for (i = 0; i < arraySize; ++i)
    {
        if(isprint(asciiValue[i])!= 0)
        {
            //print
            printf("%c ", asciiValue[i]);
        }
    }

    return 0;
}

Output:

Nothing will be printed.

Table of non-printable ASCII characters:

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