isdigit in c

What is isdigit in c programming?

isdigit in c checks the passed character is decimal digit or not.

This function is defined in ctype.h header file.

This function returns non-zero digit if passed character is decimal value otherwise zero.

Prototype

int isdigit(int a);

Parmeter of isdigit in c

This function takes character as input parameter and converts it into ASCII value.

Return value of isdigit in c

This function returns non-zero value if passed character is digit otherwise zero.

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Example program for isdigit function in c

#include<stdio.h>
#include<ctype.h>
int main()
{
  int x='2';
  int b='a';
  printf("The passed value is %d \n",isdigit(x));
  printf("The passed value is %d \n",isdigit(b));
  return 0;
}

Code explanation

isdigit function is called to check whether the passed character is a decimal digit or not. The result is being printed onto the console.

isdigit() Man page

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Difference between isdigit and isalpha in c

isdigit function checks the passed character is a decimal digit or not. isalpha function checks the passed parameter is alphabet or not.

Prototypes are as follows

int isdigit(int a);

int isalpha(int a);

isdigit function in c	isalpha function in c
Checks the passed character is decimal digit or not.	Checks the passed parameter is alphabet or not.
int isdigit(int a);	int isalpha(int c);

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Difference between isdigit and isxdigit in c

isdigit function checks the passed character is a decimal digit or not. isxdigit function checks the passed character is hexadecimal or not.

Prototypes are as follows

int isdigit(int a);

int isxdigit(int a);

isdigit	isxdigit
Checks the passed character is decimal digit or not.	Checks the passed character is hexadecimal or not.
int isdigit(int a);	int isxdigit(int a);

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