Question

INFIX2POSTFIX.CPP

#include "stack.hpp"

using namespace std;

// Auxiliary method, you probably find it useful

// Operands are all lower case and upper case characters

bool isOperand(char c){

  return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');

}

// Auxiliary method, you probably find it useful

int precedence(char c)

{

  if(c == '+' || c == '-'){

    return 0;

  }

  if(c == '*' || c == '/'){

    return 1;

  }

  if(c == '^'){

    return 2;

  }

  return -1;

}

int main(){

  freopen("input_infix2postfix.txt", "r", stdin);

  string input;

  string solution;

  int line_counter = 0;

  while(cin >> solution){

    cin >> input;

    Stack<char> stack;

    string result;

     //The input file is in the format "expected_solution infix_expression",

     //where expected_solution is the infix_expression in postfix format

    for(int i=0; i<input.length(); ++i){

      // WRITE CODE HERE to store in 'result' the postfix transformation of 'input'

    }

    

    // You need to do some extra stuff here to store in 'result' the postfix transformation of 'input'

    

    // Checking whether the result you got is correct

    if(solution == result){

      cout << "line " << line_counter << ": OK [" << solution << " " << result << "]" << endl;

    }else{

      cout << "line " << line_counter << ": ERROR [" << solution << " " << result << "]" << endl;

    }

    line_counter++;

  }

}

Implement a stack and solutions to the following problems: balancing parenthesis, evaluating postfix expressions and transforming infix expressions into postfix expressions.

infix2postfix.cpp

- create main method to transform an infix expression into postfix

Answer 1

 INFIX2POSTFIX.CPP #include "stack.hpp" using namespace std; // Auxiliary method, you probably find it useful // Operands are all lower case and upper case characters bool isOperand(char c) {     return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'); } // Auxiliary method, you probably find it useful int precedence(char c) {     if(c == '+' || c == '-') {     return 0;   }   if(c == '*' || c == '/') {     return 1;   }   if(c == '^') {     return 2;   }   return -1; } int main() {   freopen("input_infix2postfix.txt", "r", stdin);   string input;    string output; //output string   string solution;   string dummy;   string here;     int j = 0;     int con;   int line_counter = 0;   while(cin >> solution) {     cin >> input;     Stack<char> stack;     string result;   //The input file is in the format "expected_solution infix_expression",    //where expected_solution is the infix_expression in postfix format int x = 0; for(int i=0; i<input.length(); ++i) {   if (isOperand(input[i]) ) {     output[j++] = input[i];         cout << "output: " << output[i] << endl;     } else if (input[i] == '(' )  {     stack.push(input[i]); }     else if (input[i] == ')' ) {     while (stack.peek() != '(' )    {         output[j++] = stack.peek();         stack.pop();     }     stack.pop();         } else if (input[i] == '*' || input[i] == '/' || input[i] == '+' || input[i] == '-' || input[i] == '^') {                     stack.push(input[i]);     // cout << "input: " << stack.peek() << endl;         if (precedence(stack.peek()) >= precedence(input[i]) )         {                 output[j++] = stack.peek();              stack.pop();              }        else              { break; } }             }