PreInPostfix

#include <bits/stdc++.h>

using namespace std;

typedef long long LL;

// Return precedence of operator
int op_prec(string op){
    //if(op == "(" || op == ")")return 0x100;
    if(op == "!")return 0x50;
    if(op == "^")return 0x30;
    if(op == "*" || op == "/" || op == "%")return 0x20;
    if(op == "+" || op == "-")return 0x10;
    if(op == "!" || op == ">" || op == "<" || op == ">=" ||
       op == "<=" || op == "=="){return 0x08;}
    if(op[0] == '&' || op[0] == '|' || op == ">>" || op == "<<")return 0x05;
    return 0;
}

bool is_operator(string op){
    if(op == "+" || op == "-" || op == "*" || op == "/" ||
       op == "%" || op == "^" || op == "!" || op == "&" ||
       op == "&&" || op == "|" || op == "||" || op == ">" ||
       op == ">" || op == ">=" || op == "<=" || op == "==" ||
       op == ">>" || op == "<<"){

        return true;
    }
    return false;
}

bool is_basic_operator(string op){
    if(op == "+" || op == "-" || op == "*" || op == "/" ||
       op == "%" || op == "^"){return true;}
    return false;
}

string infixToPostfix(string str){
    str = "( " + str + " )";
    stringstream ss(str);
    string op, re = "";
    stack<string> op_stack;
    while(ss >> op){
        //cout << op << ' ' << op.length() << '\n';
        if(isdigit(op[0]) || isalpha(op[0])){
            re += op;
            re += ' ';
        }
        else if(op == "("){
            op_stack.push("(");
        }
        else if(op == ")"){
            while(op_stack.top() != "("){
                re += op_stack.top();
                re += ' ';
                op_stack.pop();
            }
            op_stack.pop();
        }
        else{
            while(op_prec(op) <= op_prec(op_stack.top()) ){
                re += op_stack.top();
                re += ' ';
                op_stack.pop();
            }
            op_stack.push(op);
        }
    }
    return re;
}

map<string, int> dict;

int calc_postfix(string str){
    stringstream ss(str);
    stack<int> st;
    while(ss >> str){
        if(!is_basic_operator(str) && !isdigit(str[0])){
            return 0x80000000;
        }
        if(isdigit(str[0])){
            st.push(atoi(str.c_str()));
        }
        else if(str[0] == '+'){
            int b = st.top(); st.pop();
            int a = st.top(); st.pop();
            st.push(a + b);
        }
        else if(str[0] == '-'){
            int b = st.top(); st.pop();
            int a = st.top(); st.pop();
            st.push(a - b);
        }
        else if(str[0] == '*'){
            int b = st.top(); st.pop();
            int a = st.top(); st.pop();
            st.push(a * b);
        }
        else if(str[0] == '/'){
            int b = st.top(); st.pop();
            int a = st.top(); st.pop();
            st.push(a / b);
        }
        else if(str[0] == '%'){
            int b = st.top(); st.pop();
            int a = st.top(); st.pop();
            st.push(a % b);
        }
        else if(str[0] == '^'){
            int b = st.top(); st.pop();
            int a = st.top(); st.pop();
            st.push(pow(a,b));
        }
    }
    return st.top();
}

// Convert postfix to Prefix expression
string postfixToPrefix(string str) {
    stack<string> st;
    stringstream ss(str);
    while(ss >> str){
        if(!is_basic_operator(str) && !isdigit(str[0])){
            return "Not supported";
        }
        if(is_operator(str)){
            string b = st.top(); st.pop();
            string a = st.top(); st.pop();
            st.push(str + ' ' + a + ' '+ b + ' ');
        }
        else{st.push(str);}
    }
    return st.top();
}

bool process_input(string &str){
    cout << "Infix: ";
    bool cont = getline(cin, str);
    return cont;
}

int main(){
    string str;
    while(process_input(str)){
        string result  = infixToPostfix(str);
        string result2 = postfixToPrefix(result);
        cout << "Postfix: " << result << '\n';
        cout << "Prefix: " << result2 << '\n';
        cout << "Result: ";
        int c = calc_postfix(result);
        if(c == 0x80000000){cout << "Not supported\n";}
        else{cout << c << '\n';}
        cout << "---------------\n";
    }
    return 0;
}
/*
2 + 3 * 4
2 * ( 3 + 4 ) * 5 + 2
5 * 6 + 7
! ( A && ! ( ( B < C ) || ( C > D ) ) ) || ( C >> 2 + 2 > E )

234*+
234+*5*2+
56*7+
*/