Modify your Postfix Calculator to read entries from a file, one line at a time. For those entries that are valid, compute the value and keep a running total. Display that sum and the number of invalid entries that were in the file.We will consider a postfix expression to be invalid if:An operation is encountered, but there are not at least two entries on the stack.The postfix expression has been consumed, but there is not exactly one entry remaining on the stack.I haven't found the correct answer on here yet.How many entries in this file were invalid? (Got 39 and that was wrong)What was the sum of the valid postfix expressions in this file? (Got 545508 and that was wrong) Program:#include <iostream>#include <fstream>#include <string>#include <vector>#include <sstream>using namespace std;bool operation(char b){return b == '+' || b == '-' || b == '*' || b == '/' || b == '%';}int evaluate_posfix(const string& expression){int l, r, ans;stringstream postfix(expression);vector<int> temp;string s;while (postfix >> s){if (operation(s[0])){if (temp.size() < 2){cout << "Invalid expression: Not enough operands" << endl;return 0;}r = temp.back();temp.pop_back();l = temp.back();temp.pop_back();switch (s[0]){case '+': ans = l + r; break;case '-': ans = l - r; break;case '*': ans = l * r; break;case '/':if (r == 0){cout << "Invalid expression: Division by zero" << endl;return 0;}ans = l / r;break;case '%': ans = l % r; break;}temp.push_back(ans);}else{temp.push_back(std::stoi(s));}}if (temp.size() != 1){cout << "Invalid expression: Too many operands" << endl;return 0;}return temp[0];}int main() {string filename;cout << "Enter the filename: ";cin >> filename;ifstream inputFile("Postfix_2.txt");if (!inputFile) {cout << "Error opening file." << endl;return 0;}string line;int invalidCount = 0;int total = 0;while (getline(inputFile, line)) {int result = evaluate_posfix(line);if (result != 0) {total += result;}else {invalidCount++;}}cout << "Sum of valid expressions: " << total << endl;cout << "Number of invalid expressions: " << invalidCount << endl;inputFile.close();return 0;} File:133 -167 - 79 196 / 13 125 139 -59 -168 163 17 / + / - + + + +-14 -46 54 128 * * %147 2 + 10 / 45 * 191 % -188 %171 45 * -132 % 31 % 93 + -90 - -91 %176 - 80 147 - 89 + / 39 129 + 93 * -175 164 * 83 / %-93 163 - 4 * *174 25 99 41 187 - 177 + / * %105 33 % 1 / -37 27 -58 + 4 % + + 149 /-59 32 136 140 - / * 192 % 63 93 + + 167 % 21 -16 36 * - /99 196 /191 31 92 + * 57 - 58 198 * -57 + + 179 %7 -102 -174 65 66 * / + -37 193 / -17 28 103 109 * - 23 79 92 - -91 + 100 * + % + -126 -3 +111 18 % 35 / 163 -119 78 + 73 124 191 + 44 57 168 - 14 / + -180 140 - * * + %48 -38 -108 + + 131 -134 27 / 175 * 175 -90 - + % +120 104 % 13 - 193 -47 84 + -54 67 163 29 * % % +159 13 * 2 100 56 47 / + * -167 -152 * 168 192 -129 + 176 57 38 80 65 % + % / - * %57 172 / -168 -666 130 172 -82 -183 / - 117 - + 165 114 17 * / 154 % + 124 96 % +-133 173 + 9 107 - * 106 / 101 * -136 59 % *159 -155 -96 165 /41 33 -172 -148 - 148 38 -129 * / -18 -137 -32 - %67 126 103 % / 65 % -53 119 82 64 % 15 + / - %176 51 75 68 / 46 123 57 % * * * +122 109 74 102 116 182 - * * + %15 110 164 43 -117 167 66 * 124 -155 + - - 64 155 % % + - + /45 -57 * -81 * -41 -83 122 167 113 101 / -33 -26 + - * - -147 80 169 185 + 151 20 135 8 198 * / + * / - -* 141 122 + 156 123 *2 -157 - 108 132 77 + 22 174 12 - 32 + % - * /93 199 % 93 + 17 165 133 - 139 + * 93 - *187 160 -177 5 - 117 + % 71 / 138 -153 % - *32 1 64 72 + 108 * * 160 199 + * % -85 111 * +-136 144 - 123149 149 * 15 171 123 % % -59 * --184 178 %22 170 - 60 *25 71 * -131 192 - 57 9 - -137 -162 * % % %71 -177 %96 144 116 133 -69 176 42 * + % + % +158 22 + 99 / -49 / -84 * 181 95 15 137 39 / -65 + / * + /40 178 92 85 * 77 - + + PLEASE SHOW THE OUTPUT!!!
Write a program that accepts a string that is a space-delimited integer arithmetic expression in postfix notation. Use a stack to compute the value.
Example:
The input string 5 4 + 3 10 * + is equivalent to the infix expression (5 + 4) + (3 * 10) The answer is 39.
The algorithm is:
Take the leftmost token from the string If it is numeric (which may include a unary operator), push that token onto the stack If it is a binary operation, pop the vector twice, apply the operation, and push the result When the input string is empty, the stack will contain one entry: the final answer
Here's how the given string gets processed:
String
Stack
5 4 + 3 10 * + 4 + 3 10 * + + 3 10 + 3 10 * + 10 * * + +
<empty> 5 45 9 3 9 10 3 9 30 9 39
a
The final answer,39,is the only element in the stack after all tokens in the string have been consumed.
This problem has an extra twist. The string contains characters, so 1 0 isn't a ten, but is the char 1 followed by the char 0. You will need to convert string representations of integers (signed and unsigned) into their integer values. You'll also need to handle unary - and +.
We also have to worry about the three non-commuting operators -- / % . We will evaluate the postfix string 4 5 - as 4-5 and,likewise,will evaluate 4 5 / as 4/5 and 4 5 % as 4%5
The program should continue to accept and process input strings until the user enters a zero as input. There's no need to check for validity; all input will be well-formed postfix expressions.
Submit your .cpp source code and a screen shot of your program in action.
