Infix to Postfix

#include<iostream>
#include<cstring>
#include<stack>
#include<stdio.h>
using namespace std;

int getPrecidence(char ch)
{
    switch(ch)
    {
        case '/':
        case '*': return 2;
        case '+':
        case '-': return 1;
        default : return 0;
    }

}
int main()
{
    char infix[100];
    gets(infix);
    int size = strlen(infix);
    char ch,postfix[size];
    int i=0,j=0,precedence=0;
    stack<char> myStack;

    while(i<size)
    {
        ch = infix[i];
        if(ch == '(')
        {
            myStack.push(ch);
            i++;
            continue;
        }
        if(ch == ')')
        {
            while(!myStack.empty() && myStack.top() != '(')
            {
                postfix[j++] = myStack.top();
                myStack.pop();
            }
            if(!myStack.empty())
            {
                myStack.pop();
            }
            i++;
            continue;
        }
        precedence = getPrecidence(ch);
        if(precedence == 0)
        {
            postfix[j++] = ch;
        }
        else
        {
            while(!myStack.empty() && myStack.top() != '(' && precedence <= getPrecidence(myStack.top()) )
            {
                postfix[j++] = myStack.top();
                myStack.pop();

            }
            myStack.push(ch);
        }
        i++;
    }
    while(!myStack.empty())
    {
        postfix[j++] = myStack.top();
        myStack.pop();
    }
    cout << "Postfix conversion is...." <<endl;
    for(i=0; i<size; i++)
    {
        cout << postfix[i];
    }

}