Ok
I have an assignment for school where we are building a compiler step by step each week. This week I have to make a syntax analyzer that picks out the errors from this text file below. In the source code I have provided below I have a lexical analyzer and a symbol able that will point the types and variables. That is there just so you can see what I am working with.
The syntax analyzer is supposed to point out errors in the text file file in lines 3 and 4. No semicolon and undeclared identifier.
What I am confused about is how do I get it so that my program can look for specific line in the text and list them onto the screen. Once I figure out this part I finish my assignment. Thanx in advance.
/////start of text file
main()
{
int i
j = 23;
}
///////end of text file
#include <stdio.h>
#include <stdlib.h>
#include <iostream>
#include <string.h>
#include <sstream>
#include <fstream>
#include <ctype.h>
#include <conio.h>
#include <time.h>
#include <math.h>
#include <dos.h>
#include <iomanip>
using namespace std;
int main(int argc, char* argv[])
{
ifstream infile ("input.txt");/*assigning infile to to the input text otherwise
the program will spit out all zeroes as the result.*/
//Variables
string Storeline;//Variable to store the line
string token = "";//variable to store the token
string Name = "";//variable to store the table name
bool Finished = false;//boolean to determine end of line read
string chump;//the string we use to input our text file
//Structure for symbol table
struct SymbolTable
{
string tokenType;
string tokenName;
}
table[1000];//this will be a constructor of sorts
//position in line read
int position = 0;
int a = 0;
cout<<"Enter the file name, don't forget to enter the txt extension as well.\n";
cin >> chump;
getline (infile, chump);/*gets the data from the txt file and converts it to a string.*/
if(!infile.is_open())//input.txt cannot be open then we get this error message.
{
cout << "cant open file!";
return 0;
}
//Read til end of file
do
{
Finished = false;
//get line from input file
getline(infile, Storeline);
if(!infile.eof())
{
//do... while until line is read
do
{
char character = Storeline[position++];
if((character >= 'a' && character <= 'z') || (character >= 'A' && character <= 'Z'))
{
token = token + character;//here we tokenize each alphabetical character
}
else if(character == '(' || character == ')' || character == '{' || character == '}' || character == ';'
|| character == '=' || character == '+' || character >= 0 || character <= 0)
//We tokenize the symbols that are not letters
{
if(token == "int" || token == "double" || token == "char")
//here we specifiying what the symbol table should look for
{
table[a].tokenType = token;//We search our symbol table for the Token types
while(character != ';')//I need this semicolon so the variable names will show up.
{
character = Storeline[position++];
Name = Name + character;
}
table[a].tokenName = Name;//We search our symbol table or the Token Names
a++;
}
cout << token << endl;
if(Name != "")
{
cout << Name << endl;
}
token = "";//displays variable type
Name = "";//displays variable itself
cout << character << endl;
}
if (position >= Storeline.length())
{
Finished = true;
position = 0;
}
}while(!Finished);
}
}while(!infile.eof());
//close input file
infile.close();
//table format
cout << "Type Variable Name\n";
//loop to display each of the symbol tables data
for(int f = 0; f < a; f++)
{
cout << table[f].tokenType << " " << table[f].tokenName << endl;
}
system("pause");
return 0;
}
