Getting a segmentation fault on my post-fix calculator

Question

I'm trying to write a post-fix/reverse polish calculator, only that before each number, there will be a '#', before each operator, a '!', and a '.' to signify the end of the expression. One space between each number/character/etc. I don't care about error-checking.

I understand that you can use stringstream here, but I still think that it should be able to work without it.

The input, entered into the console, would look something like,

# 33 # 3 ! / # 2 ! *.

which would then output 22. I am currently getting a segmentation fault with the below code.

Thanks for looking.

#include <iostream>
#include <cstdlib>
#include <math.h>

using namespace std;

class Stack{   
    public:
    Stack(){
        this->size = 0;
    }

    Stack & push(double c){
        if (size == MAX_SIZE) die("Push Overflow");
        data[size] = c;
        size++;
        return *this;
    }

    double pop(){
        return data[--size];    
    }

    double top() const{
        return data[size-1];
    }

    unsigned getSize() const{return size;}

    bool die(const string & msg){   
        cerr << "Fatal Error: " << msg << endl;
        exit(EXIT_FAILURE);   
    }

    void show(){   
        for (int i = 0; i < size; i++){
            cout << data[i] << endl;
    }}

    private:

    static const unsigned MAX_SIZE = 50;
    double data[MAX_SIZE];
    unsigned size;
};


int main(){
    Stack s1;
    bool inputComplete = false;
    double num1 =0;
    double num2 = 0;
    double answer = 0;
    char c, ch;

    while(!inputComplete){       
        cin >> ch;   
        if (ch == '!'){
            cin >> c;

            num1 = s1.pop();
            num2 = s1.pop();

            switch(c){    

                case '+':
                answer = num2 + num1;
                break;    

                case '-':
                answer = num2 - num1;
                break;    

                case '/':
                answer = num2/num1;
                break;    

                case '^':
                answer = pow(num2, num1);
                break;    

                case '*':
                answer = num2 * num1;
                break;   
            }
            s1.push(answer);
        }    
        else if (c == '#'){  
            double number;
            cin >> number;
            s1.push(number);   
        }
        else if (c == '.'){
            inputComplete == true;
        }
    }

    s1.show();    
    return 0;
}

Answer 1

Problems I found:

The line

    else if (c == '#'){  

should be

    else if (ch == '#'){  

The line

    else if (c == '.'){  

should be

    else if (ch == '.'){  

The line

        inputComplete == true;

should be

        inputComplete = true;

Update

I realize that you don't want any error checking code. But a minimal amount of error checking is useful. To that end, I think you should check when EOF is reached.

    ch = cin.get();
    if ( ch == EOF )
    {
       inputComplete = true;
    }
    else if (ch == '!'){

instead of

    cin >> ch;
    if (ch == '!'){

makes sense to me.

Answer 2

At the end there is

else if (c == '.'){
    inputComplete == true;
}

but it should be

else if (c == '.'){
    inputComplete = true;
}