Lexical Analyzer
Simple Lexical Analyzer program. It takes the filename in the same directory as the input and analyzes the program for variables operators and special characters. and prints the output for each values separately.
#include<stdio.h>
#include<conio.h>
#include<string.h>
void main()
{
FILE *fp;
int i=0;
char input[100],filename[20];
clrscr();
printf("Enter Filename : ");
scanf("%s",filename);
fp=fopen(filename,"r");
while(!feof(fp))
{
input[i]=fgetc(fp);
i++;
}
input[--i]='\0';
for(i=0;i<strlen(input);i++)
{
if(isalpha(input[i]))
{
printf("%c is a Character.\n",input[i]);
}
else if(input[i]=='='||input[i]=='+'||input[i]=='-'||input[i]=='*'||input[i]=='/'||input[i]=='%')
{
printf("%c is an Operator.\n",input[i]);
}
else if(isspace(input[i])||iscntrl(input[i]))
{
}
else if(isdigit(input[i]))
{
printf("%c is a number.\n",input[i]);
}
else
{
printf("%c is a Special character.\n",input[i]);
}
}
getch();
}
