Write a program to Implement Shift Reduce parsing for a String.

 #include <iostream>

#include <stack>

#include <vector>

#include <unordered_map>

using namespace std;

vector<string> productions = {"E->E+T", "E->T", "T->T*F", "T->F", "F->(E)", "F->id"};

unordered_map<string, unordered_map<string, string>> parsingTable = {

    {"E", {{"(", "shift T"}, {"id", "shift T"}}},

    {"T", {{"(", "shift F"}, {"id", "shift F"}}},

    {"F", {{"(", "shift (E)"}, {"id", "shift id"}}}

};

void shift(stack<string> &parseStack, vector<string> &input) {

    parseStack.push(input[0]);

    input.erase(input.begin());

}

void reduce(stack<string> &parseStack, const string &nonTerminal) {

    if (parsingTable.find(nonTerminal) != parsingTable.end()) {

        string production = parsingTable[nonTerminal]["$"];

        size_t arrowPos = production.find("->");

        string rhs = production.substr(arrowPos + 2);

        for (size_t i = 0; i < rhs.size(); ++i) {

            parseStack.pop();

        }

        parseStack.push(production.substr(0, arrowPos));

    } else {

        cout << "Error: No production rule for non-terminal " << nonTerminal << endl;

    }

}

void parse(stack<string> &parseStack, vector<string> &input) {

    while (!input.empty()) {

        string stackTop = parseStack.top();

        string nextInput = input[0];

        if (parsingTable[stackTop].find(nextInput) != parsingTable[stackTop].end()) {

            string action = parsingTable[stackTop][nextInput];

            if (action.substr(0, 5) == "shift") {

                shift(parseStack, input);

            } else if (action.substr(0, 5) == "reduce") {

                reduce(parseStack, stackTop);

            }

        } else {

            cout << "Error: Invalid pair (" << stackTop << ", " << nextInput << ")" << endl;

            break;

        }

        cout << "Stack: ";

        stack<string> tempStack = parseStack;

        while (!tempStack.empty()) {

            cout << tempStack.top() << " ";

            tempStack.pop();

        }

        cout << "\tInput: ";

        for (const auto &symbol : input) {

            cout << symbol << " ";

        }

        cout << endl;

    }

}

int main() {

    vector<string> input = {"id", "+", "id", "*", "id", "$"};

    stack<string> parseStack;

    parseStack.push("E");

    parse(parseStack, input);

    return 0;

}