isgraph
Header: <ctype.h>
Checks if the given character has a graphical representation, i.e. it is either a number (0123456789), an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), a lowercase letter (abcdefghijklmnopqrstuvwxyz), or a punctuation character (!"#$%&’()*+,-./:;<=>?@[]^_`{|}~), or any graphical character specific to the current C locale.
# Declarations
int isgraph( int ch );
# Parameters
ch: character to classify
# Return value
Non-zero value if the character has a graphical representation character, zero otherwise.
# Example
#include <stdio.h>
#include <ctype.h>
#include <locale.h>
int main(void)
{
unsigned char c = '\xb6'; // the character ¶ in ISO-8859-1
printf("In the default C locale, \\xb6 is %sgraphical\n",
isgraph(c) ? "" : "not " );
setlocale(LC_ALL, "en_GB.iso88591");
printf("In ISO-8859-1 locale, \\xb6 is %sgraphical\n",
isgraph(c) ? "" : "not " );
}