The isdigit() function defined in the ctype.h header file. It helps to check the specified character is a decimal digit or a numeric(0-9).
int isdigit( int argument ); #where argument will be a character
The isdigit() function takes a single parameter and is in the form of an integer and the return value should be an integer. When a character is passed it is converted into the integer value corresponding to its ASCII value.
| Parameter | Description | Required / Optional |
|---|---|---|
| argument | The character to be checked | Required |
If the given character is a numeric character, isdigit() returns a non-zero integer else zero. When the numeric character is passed we will get a different non-zero integer.
| Input | Return Value |
|---|---|
| Zero | If the parameter is not a numeric character |
| Non zero number | If the parameter is a numeric character |
#include <stdio.h>
#include <ctype.h>
int main()
{
char ch;
ch='4';
printf("If numeric character is passed: %d", isdigit(ch));
ch='+';
printf("\nIf non-numeric character is passed: %d", isdigit(ch));
return 0;
}
Output:
If numeric character is passed: 1 If non-numeric character is passed: 0
#include <stdio.h>
#include <ctype.h>
int main()
{
char ch;
printf("Enter any character: ");
scanf("%c",&ch);
if (isdigit(ch) == 0)
printf("The given %c is not a digit.",ch);
else
printf("The given %c is a digit.",ch);
return 0;
}
Output:
Enter any character: 4 The given 4 is a digit.
