by Dinesh Thakur

 

 

#include<ctype.h>

#include<stdio.h>
#include<conio.h>
void main()
{
char ch;
for(;;){
ch = getc(stdin);
if(ch == '.') break;
if(isalnum(ch)) printf("%c is alphanumeric\n", ch);
}
getch();
}
 
OUTPUT:
s4
s is alphanumeric
4 is alphanumeric