Thread: Stack Program Error

This is the stack project I had to make. I'm posting my code after what the project is supposed to be. and then I'll post the error i get from compiling that i can't figure out.

What Project Is.

Project:

For this project you will write a program that will read in strings from a file named "reverse.in". Each word may be marked with an even number of "at" characters ('@'). The first '@' character signals that the following characters up to the next '@' are in reverse order. Your program will print the result to an output file called "reverse.out". You must use an STL stack to reverse the order of the characters.

For example, if the input file looks like this:

@egelloC@
CS174
re@srev@e
sup@ilacre@fragilist@ilaipxeci@docious
id@@en@@ti@@ty

then the output would be:

College
CS174
reverse
supercalifragilisticexpialidocious
identity

code i wrote

Code:

#include <stack>
#include <iostream>
#include <fstream>

using namespace std;
int main()
{
int i;
bool forward;
string word;
stack<char> letter;
string   inFileName = "reverse.in";
string   outFileName = "reverse.out";
ifstream inFile;
ofstream outFile;
  
inFile.open(inFileName.c_str());
outFile.open(outFileName.c_str());
forward = true;

inFile.getline(word);
while(inFile)
{
	for(i=0;i<=word.length();i++)
	{
		if(forward)
		{
			outFile << word[i];
			if(word[i] == '@')
			{
				forward = false;
			}
		}
		else(!forward)
		{
			if(word[i]!='@')
			{
				letter.push(word[i])				
			}
			else if(word[i] == '@')
			{
				forward = true;
				while(!letter.empty)
				{
					outFile << letter.top();
					letter.pop;
				}
			}
		}
	}
  inFile.close();          
  outFile.close();
  return 0;
};

the error i get from compiling

Code:

main.cpp: In function ‘int main()’:
main.cpp:21: error: no matching function for call to ‘std::basic_ifstream<char, std::char_traits<char> >::getline(std::string&)’
/usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../include/c++/4.1.2/istream:581: note: candidates are: std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::getline(_CharT*, std::streamsize, _CharT) [with _CharT = char, _Traits = std::char_traits<char>]
/usr/lib/gcc/i486-linux-gnu/4.1.2/../../../../include/c++/4.1.2/istream:397: note:                 std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::getline(_CharT*, std::streamsize) [with _CharT = char, _Traits = std::char_traits<char>]
main.cpp:35: error: expected `;' before ‘{’ token
main.cpp:54: error: expected `}' at end of input

I looked at like 35 and line 54 but i have what the compiler is talking about, and I have no idea what the first error I have is. Thanks in advance.

Code:

else(!forward)

>> inFile.getline(word);
There is a different version of getline for strings. Use:

Code:

getline(inFile, word);

my only error now is

Code:

main.cpp: In function ‘int main()’:
main.cpp:36: error: expected `;' before ‘{’ token

Code:

#include <stack>
#include <iostream>
#include <fstream>
#include <string>

using namespace std;
int main()
{
int i;
bool forward;
string word;
stack<char> letter;
string   inFileName = "reverse.in";
string   outFileName = "reverse.out";
ifstream inFile;
ofstream outFile;
  
inFile.open(inFileName.c_str());
outFile.open(outFileName.c_str());
forward = true;

getline(inFile,word);
while(inFile)
{
	for(i=0;i<=word.length();i++)
	{
		if(forward)
		{
			outFile << word[i];
			if(word[i] == '@')
			{
				forward = false;
			}
		}
		else(!forward)
		{
			if(word[i]!='@')
			{
				letter.push(word[i]);				
			}
			else if(word[i] == '@')
			{
				forward = true;
				while(!letter.empty)
				{
					outFile << letter.top();
					letter.pop;
				}
			}
		}
	}
	getline(inFile,word);
}
  inFile.close();          
  outFile.close();
  return 0;
};

See anon's post. That's not legal syntax. A simple else will do.

This is the code I have:

Code:

#include <stack>
#include <iostream>
#include <fstream>
#include <string>

using namespace std;
int main()
{
int i;
bool forward;
string word;
stack<char> letter;
string   inFileName = "reverse.in";
string   outFileName = "reverse.out";
ifstream inFile;
ofstream outFile;
  
inFile.open(inFileName.c_str());
outFile.open(outFileName.c_str());
forward = true;


getline(inFile,word);
while(inFile)
{
	for(i=0;i<=word.length();i++)
	{
		if(forward)
		{
			outFile << word[i];
			if(word[i] == '@')
			{
				forward = false;
			}
		}
		else
		{
			if(word[i]!='@')
			{
				letter.push(word[i]);				
			}
			else if(word[i] == '@')
			{
				forward = true;
				while(!letter.empty())
				{
					outFile << letter.top();
					letter.pop();
				}
			}
		}
	}
	getline(inFile,word);
}
  inFile.close();          
  outFile.close();
  return 0;
};

in the reverse.out file i have @tsal@ and when i ran the program it printed @tsal^@...what am i doing wrong here? Its not supposed print the @ signs.

>> Its not supposed print the @ signs.
Then don't print the @ signs. You already have if statements in there to determine if the character is an @ or not.

Also, you didn't fix the second part of laserlight's first post. Your loop still runs one extra time.

ok i think i fixed the loop issue laserlight pointed out...how would i decide not to print the @ sign?...also at the end of each line ^@ is printed idk what that is from. heres my updated code:

Code:

#include <stack>
#include <iostream>
#include <fstream>
#include <string>

using namespace std;
int main()
{
int i;
bool forward;
string word;
stack<char> letter;
string  inFileName = "reverse.in";
string  outFileName = "reverse.out";
ifstream inFile;
ofstream outFile;
  
inFile.open(inFileName.c_str());
outFile.open(outFileName.c_str());
forward = true;


getline(inFile,word);
while(inFile)
{
	for(i=1;i<=word.length();i++)
	{
		if(forward)
		{
			outFile << word[i];
			if(word[i] == '@')
			{
				forward == false;
			}
		}
		else if(!forward)
		{
			if(word[i]!='@')
			{
				letter.push(word[i]);				
			}
			else if(word[i] == '@')
			{
				forward = true;
				while(!letter.empty())
				{
					outFile << letter.top();
					letter.pop();
				}
			}
		}
	}
	outFile << endl;
	getline(inFile,word);
}
  inFile.close();          
  outFile.close();
  return 0;
};

Nope, you haven't fixed what laserlight pointed out. The answer is in "for(i....)". And i should start from 0.

Also, you need to nest "outfile << word[i]" inside another conditional so that @ does not get printed.