Need help with lexical analyzer

[Code Oranj]

I have assignment to write a simple lex anayzer. I can't get the output to print the tokens correctly.

All that should print is the characters from a file, and their assigned token. Mine just ends in DIGIT DIGIT DIGIT every time (because i have "int token = 0". If i change the value it just changes the constant token name. Due tonight, and feeling desperate. Please show my what I am doing wrong. Thank you so much.

CO

int main()
{					
string characters;							
ifstream foo("file name here");

while (foo >> characters)
{
int t = 0;
string convertToken(int t);
cout << characters << convertToken(t);
}

foo.close();							
return 0;
}

This prints
A DIGIT
+ DIGIT
1 DIGIT
= DIGIT
word DIGIT

etc etc
it should print
A LETTER/WORD
+ PLUS
1 DIGIT
= EQUAL
word LETTER/WORD

Please help me.
CO

[Zhuge]

What does convertToken() do?

[Code Oranj]

string convertToken(int token) 
{
  switch (token) 
  {
	case LETTER: return "<LETTER/WORD>";
  	case DIGIT:  return "<DIGIT>";
	case PLUS:  return "<PLUS>";
	case ASSIGN:  return "<ASSIGN>";
  }
}

[Zhuge]

I think that after reading into characters, you should look at it and determine its type. Then set token to whatever that type is.

[Code Oranj]

how?

[Zhuge]

I think that's part of the point of your assignment; based on the list you've given, however, if the string contains characters, it is a "LETTER/WORD", if it is the plus sign, it is "PLUS", and so on.

[Code Oranj]

It is part of the point of the assignment. Setting up all the code you cannot see is another part. And, after many many days I cannot figure out how to do it, so in desperation I am coming for help.

If i code it so that it takes information from user input, it works correctly. When I switch it to take the information from a file, something breaks. I cannot figure out what is wrong, and I am asking for straight up help at this point. Please.

[Mats]

"something breaks" Can you be a little descriptive? What exactly breaks?

[Code Oranj]

before it printed:
A <LETTER/WORD>
+ <PLUS>
1 <DIGIT>
= <ASSIGN>
word< LETTER/WORD>


now that i am asking it to extract the information from a file, it prints
A <DIGIT>
+ <DIGIT>
1 <DIGIT>
= <DIGIT>
word <DIGIT>

That is what I mean by it "breaking"

[Code Oranj]

I solved it.

//class Scan

int main()
{
	string characters;								
	string convertToken(int t);
	int t = true;

	ifstream foo("file name here");	

	while (foo >> characters)
	{
		Scan items = characters;
		token = items.lex();
		cout << characters << convertToken(t);
	}

	foo.close();
	return 0;
}

This opens the file, prints the contents by character leaving strings in tact, and assigns each string a token.

For example:
A  <LETTER/WORD>
+ <PLUS>
B <LETTER/WORD>
= <ASSIGN>
7 <DIGIT>
success <LETTER/WORD>

The supporting code that operates this outcome is not shown.