Data-Structure-Programs/infix_to_postfix.cpp at master · akshay2742/Data-Structure-Programs · GitHub

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#include<iostream>
#include<bits/stdc++.h>
#include<cstring>
#include<cctype>
using namespace std;
int prec(char c)
{
    if (c=='*' || c=='/')
        return 2;
    else if (c=='+' || c=='-')
        return 1;
    else
        return -1;
}
void infix_to_postfix(string s)
{
    std:: stack <char> st;
    int i;
    char p;
    string a;
    int l= s.length();
    for(i=0;i<l;i++)
    {

        if(isdigit(s[i]))
        {

            a+=s[i];
        }
        else if (s[i]=='(' )
        {

            st.push(s[i]);

        }
        else if (s[i]==')')
        {
            while(st.top()!='(')
            {
                p=st.top();
                st.pop();
                a=a+p;
            }
            if(!st.empty())
            {

                st.pop();

            }

        }
        else
        {
             while(prec(s[i]) < prec(st.top()))
            {
                char ch = st.top();
                st.pop();
                a+= ch;
            }
            st.push(s[i]);
        }


    }
    cout<<a<<endl;
}
int main()
{
    string exp = "(((2+3*4/8)+5)*6)";

    infix_to_postfix(exp);

    return 0;
}