Question

i am working on this program ,but i am receiving 2 errors , i cant know what they mean or how i fix them ….
the program should read any equation as a+b-c or (a+b)-c …etc
and check if the parenthesis match or not
here is the code

// A simple Integer stack, Array based
#include <string>
#include <iostream>
#define STACK_MAX 100
#define equation

using namespace std;
template <typename type>
class Stack {

private:
    type        data[STACK_MAX];
    int        size;

public:
    Stack();
    ~Stack() { }   // Destructor
    int top();
    void push(int d) ;
    void pop() ;
    int is_full ();
    int is_empty () ;
    void equal( Stack& entry) ;
};
template <typename type > int Stack<type>::is_full () {
    return ( STACK_MAX >= size );
}
template <typename type > int Stack<type>::is_empty () {
    return ( STACK_MAX == 0 );
}
template <typename type>  Stack <type>::Stack() {
    size = 0;
}
template <typename type > int Stack< type >:: top() {

    if (is_empty ()) {
        printf("Error: stack empty\n");
        return -1;
    }
    return data[size-1];
}
template <typename type > void Stack <type>::push (int d) {

    if (! is_full () ) {
        data[size++] = d;
    } else {
        printf("Error: stack full\n");
    }
}
template < typename type > void Stack <type>::pop() {

    if (size == 0) {
        printf("Error: stack empty\n");
    } else {
        size--;
    }
}
template <typename type > void Stack <type> ::equal ( Stack& entry ) {
    std::string& equation ;
    char left = '(' ;
    char right= ')' ;
    Stack <type> x ;
    string::size_type a ;
    char next ;
    next = entry ;
    bool failed = false ;
    for ( a= 0 ; ! equation.length() ; ++a) {
        next = equation[a] ;
        if ( next == left ) {
            x.push (next);
        } else {
            if (x.is_empty()) {
                x.pop () ;
            } else {
                failed = true ;
            }
        }

    }
    if ( a == 0) {
        cout << " No parenthesis"<< endl ;
    } else if ( x.top () == left ) {
        cout << "Parenthesis don’t match. Missing right parenthesis" << endl ;
    } else if ( x.top () == right ) {
        cout << "Parenthesis don’t match. Missing left parenthesis " << endl ;
    } else {
        cout << "Matching parenthesis" << endl ;
    }

}


int main() {

    Stack <char> equation2 ;
    char b ;
    cout << " please enter your equation " << endl ;
    for (int i =0 ; i< 100 ; i++ ) {

        cin >> b ;
        equation2.equal(b) ;
    }


    system ("pause") ;


    return 0;
}

and here are the errors

    2   IntelliSense: a reference of type "Stack<char> &" (not const-qualified) cannot be initialized with a value of type "char"   c:\users\mike\documents\visual studio 2010\projects\stack\stack\stack.cpp   101
   Error    1   error C2664: 'Stack<type>::equal' : cannot convert parameter 1 from 'char' to 'Stack<type> &'   c:\users\mike\documents\visual studio 2010\projects\stack\stack\stack.cpp   101

Answer 1

The previous answer was for some reason deleted so I guess I’ll post one instead.

As you said, equal’s current implementation depends on the type to work on is a char, which would render changing the signature to type& quite meaningless because it would still only work as expected if you instantiated the templated class using the type char. Still, the current problem is that the equal signature takes a Stack& which is wrong, you should change to char

template <typename type > void Stack <type> ::equal ( Stack& entry ) 

to

template <typename type > void Stack <type> ::equal ( char& entry )