C language isdigit() function: determine whether a character is a decimal number

Function name : isdigit

Header file : <ctype.h>

Function prototype : int isdigit(int ch);

Function : Determine whether the character is a decimal number

Parameters : int ch character to be checked

Return value : If ch is not a decimal number, return 0. If ch is a decimal number, return non-0.

Program example : Determine whether the entered character is a decimal number

 #include<ctype.h>#include<stdio.h>intmain(){charch;printf(inputacharacter:);scanf(%c,&ch);if(isdigit(ch)){printf(%cisdigit.,ch) ;}else{printf(%cisnotdigit.,ch);}putchar('n');return0;}

Running results:

 inputacharacter:55isdigit.