infix to postfix converter

STACK_infix-to-postfix.cpp

#include <iostream>
#include <stack>
#include <cmath>

using namespace std;

bool isOperator(char x)
{
    if(x == '+' || x == '-' || x == '*' || x == '/' || x == '^')
    {
        return true;
    }
    else return false;
}


bool isOperand(char x)
{
    if( (x >= '0' && x<='9') || (x >= 'a' && x<='z') || (x >='A' && x<='Z') )
    {
        return true;
    }
    else return false;
}

bool isLowOperator(char x, char y)
{
    int valX = 0, valY = 0;

    if(x=='*' || x=='/')
    {
        valX = valX + 1;
    }
    if(x=='^')
    {
        valX = valX + 2;
    }


    if(y=='*' || y=='/')
    {
        valY = valY + 1;
    }
    if(y=='^')
    {
        valY = valY + 2;
    }

    if(valX < valY)
    {
        //cout<<x<<"is lower than"<<y<<endl;
        return true;
    }
    else return false;

}

int main()
{

    /*
    Infix to postfix
    */

{
        stack<char> myStack;

        string infix = "2*3/(2-1)+5*3";
        infix = infix + ')';


        myStack.push('(');

        string p = "";

        int len = infix.length();

        for(int i =0; i<len &&  myStack.empty() != true; i++)
        {
            if(isOperand(infix[i]))
            {
                p = p + infix[i];
            }
            else if(infix[i] == '(')
            {
                myStack.push(infix[i]);
            }
            else if( isOperator(infix[i]) )
            {
                while( isOperator(myStack.top()) && (isLowOperator(infix[i],myStack.top()) != true))
                {
                        p = p + myStack.top();
                        myStack.pop();
                }

                myStack.push(infix[i]);

            }

            else if( infix[i] == ')' )
            {
                while(myStack.top() != '(')
                {
                    p = p + myStack.top();
                    myStack.pop();
                }

                myStack.pop();
            }

            cout<<"STEP "<<i<<" : "<<p;
                    if(!myStack.empty()){
                cout<<myStack.top();}
        cout<<endl;
        }

        cout<<endl<<"RESULT : "<<p<<endl;

}



    return 0;
}