#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<ctype.h>
void main(){
FILE *input = fopen("lex.txt","r");
char buffer[100];
int n=0,i;

do {
char c = fgetc(input);

if(c=='+'||c=='-'||c=='*'||c=='/'||c=='%'||c=='=') {
if(strncmp("int",buffer,n)==0||strncmp("float",buffer,n)==0||strncmp("if",buffer,n)==0||strncmp("else",buffer,n)==0||strncmp("printf",buffer,n)==0) {
printf("%s is a keyword\n",buffer);
for(i=0;i<10;i++) {
buffer[i]='\0';

}
n=0;
}
else {
printf("%s is a identifier\n",buffer);
for(i=0;i<10;i++) {
buffer[i]='\0';

}
n=0;
}
printf("%c is an operator\n",c);
}
else if(isalnum(c)) {
buffer[n++]=c;
}


if(feof(input))
break;

}while(1);
printf("%s is a identifier\n\n",buffer);


}