#include<stdio.h>
#include<conio.h>
#include<string.h>
#include<ctype.h>
void main()
{
int i=0,flag=0;
char
a[10][10]={"int","float","break","long","char","for","if","switch","else","while"},string[10];
clrscr();
printf("Enter a string :");
gets(string);
/*----Checking whether the string is in
array a[][]----*/
for(i=0;i<10;i++)
{
if((strcmp(a[i],string)==0))
flag=1;
}
/*----If it is in the array then it is a
keyword----*/
/*----Otherwise check whether the string
is an identifier----*/
if(flag==0)
{
/*----Checking the
1st character*----*/
if((string[0]=='_')||(isalpha(string[0])!=0))
{
/*---Checking rest of the characters*---*/
for(i=1;string[i]!='\0';i++)
if((isalnum(string[i])==0)&&(string[i]!='_'))
flag=1;
}
else
flag=1;
if( flag==0)
printf("\n%s is an identifier ",string);
else
printf("\n%s is not an identifier ",string);
}
getch();
}
Output :
