Why do I get these errors in the If statements?

Code:

---

#include<iostream>
#include<fstream>
#include<iomanip>
#include<cstdlib>
#include<string>
#include"StackLLImple.cpp"

using namespace std;

int main()
{
    char answer;
        //char InputChar1, InputChar2;
    int num;
    int success=0;
        string InputChar1;
        string InputChar2;

        character link;

        ifstream InFile;
        ofstream OutFile;

        InFile.open("input.txt");
    OutFile.open("output2.txt");

    OutFile << "This is the the linked list function" << endl;
    OutFile<< "\n \n";

        InFile>>InputChar1;
        InFile>>InputChar2;
        while(InFile != NULL)
        {


        if((InputChar1 == '{') || (InputChar2 == '}'))  //errors here
        {
                success = link.push(num, success);
        }
        else if((InputChar1 == '(') || (InputChar2 == ')')) //error here
        {
                success = link.push(num, success);
        }
        else //if(InputChar1 != InputChar2)
                success=link.pop(num, success);
        OutFile<<InputChar1;
        OutFile<<InputChar1;

        InFile>>InputChar1;
        InFile>>InputChar2;
        }
retturn 0
}

---

It would help if you posted the errors.

Also, you might want to post StackLLImple.cpp.

:\Documents and Settings\Andrew\Desktop\Important stuff\ACS 279\Program1\stackLLClient.cpp(36) : error C2676: binary '==' : 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' does not define this operator or a
conversion to a type acceptable to the predefined operator
C:\Documents and Settings\Andrew\Desktop\Important stuff\ACS 279\Program1\stackLLClient.cpp(36) : error C2676: binary '==' : 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' does not define this operator or a
conversion to a type acceptable to the predefined operator
C:\Documents and Settings\Andrew\Desktop\Important stuff\ACS 279\Program1\stackLLClient.cpp(40) : error C2676: binary '==' : 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' does not define this operator or a
conversion to a type acceptable to the predefined operator
C:\Documents and Settings\Andrew\Desktop\Important stuff\ACS 279\Program1\stackLLClient.cpp(40) : error C2676: binary '==' : 'class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >' does not define this operator or a
conversion to a type acceptable to the predefined operator
Error executing cl.exe.

stackLLClient.obj - 4 error(s), 0 warning(s)

Code:

---

#include<iostream.h>
#include"stackLL.h"

//constructor
character::character()
{
    head=NULL;
    cur=NULL;
    pre=NULL;
}

//destructor
character::~character()
{
    node *ptr;

    while(head!=NULL)    //delete all the numbers
    {
        ptr=head->next;
        delete head;
        head=ptr;
    }
}

int character::push(int num, int success)
{

    if(head==NULL)
    {
        head=new node;
        head->num=num;
        head->next=NULL;
        success=1;
    }
    else
    {
        cur=head;
        head=NULL;
        head=new node;
        head->num=num;
        head->next=cur;
        success=1;
    }

    return success;

}


//****remove at the head, this is stack, push at the head remove at the head.
int character::pop(int num, int success)
{
    node *temp;                          //make a temp pointer

    if(head!=NULL)              //if the list is not empty
    {
        temp=head->next;      //temp equal to head ->next
        delete head;          //delete head, remove the first data of the list
        head=temp; //now the second data of the list become the first data of the list
        return success=1;          //return success
    }

    else
        return success=0;          //if the list empty return fail

    return success;
}


//this function will print from the beginning of the list to the end of the list
void character::print()
{
    //if the list was empty print out an error message
    if(head==NULL)
    {
        cout << "There isn't any number" << endl;
        return;
    }

    //else while not the end of the list, print out the number and go to the next one
    else
    {
        cur=head;
        while(cur!=NULL)
        {
            cout << "number: " << cur->num << endl;
            cur=cur->next;
        }
    }
}


//the search function was search from the beginning of the head to the end of the
//head.
int character::search(int num, int success)
{

    if(head==NULL)    //if there isn't any data return 0
    {
        success=0;
        return 0;
    }

    if(head->num == num)        //if delete the first node
    {
        cout << num << " was found" << endl;
        success=1;
        return 1;
    }
    else        //else delete any node other than the first node
    {
        cur=head;
        cur=cur->next;


        while(cur!=NULL)    //search all the to the end of the list
        {

            if(cur->num ==num)
            {
                cout << num << " was found" << endl;
                success=1;

                return 1;
            }
            pre=cur;
            cur=cur->next;
            success=0;
        }// while
    } //else
return success;
}

---

You can't compare strings to individual characters. Try doing:

Code:

---

if(InputChar1 == "{" .....

---

instead of using the single quotes. That should probably get rid of the errors, or if it doesn't then use:

Code:

---

(InputChar1.Compare("{") == 0)

---

A more specific question: Why isn't my program pushing and poping correctly?
Stack program: Develop a stack class using a linked list representation and string data and use it in a program that check C++ programs for the balancing symbols (/* */, ( ), [ ], and { }). The program should read in a C++ program and output one of three messages.

Case 1: Symbol1 does not match symbol2.
Example: “(” does not match “*/”.
Case 2: End of program reached with unmatched symbol.
Example: End of program reached with unmatched “{”.
Case 3: All symbols correctly balanced.

Read the name of the program file to be check from the command line.


Input file:[] / * */ ( ) [] / * */ ( ) ( ]
[CODE]
#include<iostream>
#include<fstream>
#include<iomanip>
#include<cstdlib>
#include<string>
#include"StackLLImple.cpp"

using namespace std;

int main()
{
char answer;
//char InputChar1, InputChar2;
int num;
int success=0;
string InputChar1;
string InputChar2;

character link;

ifstream InFile;
ofstream OutFile;

InFile.open("input.txt");
OutFile.open("output2.txt");

OutFile << "This is the the linked list function" << endl;
OutFile<< "\n \n";

InFile>>InputChar1;
InFile>>InputChar2;
while(InFile != NULL)
{


if((InputChar1 == "[") || (InputChar2 == "]"))
{
success = link.push(num, success);
success = link.push(num, success);
}
else if((InputChar1 == "(") || (InputChar2 == ")"))
{
success = link.push(num, success);
}
else if((InputChar1 == "/*") || (InputChar2 == "*/"))
{
success = link.push(num, success);
}
else //if(InputChar1 != InputChar2)

success=link.pop(num, success);

OutFile<<InputChar1;
OutFile<<InputChar2;

InFile>>InputChar1;
InFile>>InputChar2;

}
return 0;
}

#include<iostream.h>
#include"stackLL.h"

//constructor
character::character()
{
head=NULL;
cur=NULL;
pre=NULL;
}

//destructor
character::~character()
{
node *ptr;

while(head!=NULL) //delete all the numbers
{
ptr=head->next;
delete head;
head=ptr;
}
}

int character::push(int num, int success)
{

if(head==NULL)
{
head=new node;
head->num=num;
head->next=NULL;
success=1;
}
else
{
cur=head;
head=NULL;
head=new node;
head->num=num;
head->next=cur;
success=1;
}

return success;

}


//****remove at the head, this is stack, push at the head remove at the head.
int character::pop(int num, int success)
{
node *temp; //make a temp pointer

if(head!=NULL) //if the list is not empty
{
temp=head->next; //temp equal to head ->next
delete head; //delete head, remove the first data of the list
head=temp; //now the second data of the list become the first data of the list
return success=1; //return success
}

else
return success=0; //if the list empty return fail

return success;
}


//this function will print from the beginning of the list to the end of the list
void character::print()
{
//if the list was empty print out an error message
if(head==NULL)
{
cout << "There isn't any number" << endl;
return;
}

//else while not the end of the list, print out the number and go to the next one
else
{
cur=head;
while(cur!=NULL)
{
cout << "number: " << cur->num << endl;
cur=cur->next;
}
}
}


//the search function was search from the beginning of the head to the end of the
//head.
int character::search(int num, int success)
{

if(head==NULL) //if there isn't any data return 0
{
success=0;
return 0;
}

if(head->num == num) //if delete the first node
{
cout << num << " was found" << endl;
success=1;
return 1;
}
else //else delete any node other than the first node
{
cur=head;
cur=cur->next;


while(cur!=NULL) //search all the to the end of the list
{

if(cur->num ==num)
{
cout << num << " was found" << endl;
success=1;

return 1;
}
pre=cur;
cur=cur->next;
success=0;
}// while
} //else
return success;
}
struct node
{
int num;
node *next;
};

class character
{
public:
character();
~character();

int push(int num, int success);
int pop(int num, int success);
void print();
int search(int num, int success);

private:
node *head;
node *cur;
node *pre;
};
[/NODE]