Making The Road Wiki

#include <iostream>
#include "Stack.h"
using namespace std;
using namespace algo;
/**
 * 逆ポーランド記法
 * P.31
 */
void reverse_polish_notation() {
  char c;
  Stack<int> acc;
  int x;
  while (cin.get(c)) {
    x = 0;
    while (c == ' ') cin.get(c);
    if (c == '+') {
      x = acc.pop() + acc.pop();
    }
    if (c == '*') {
      x = acc.pop() * acc.pop();
    }
    while (c >= '0' && c <= '9') {
      x = 10 * x + (c - '0');
      cin.get(c);
    }
    if (c != '\n') { // この条件追加
      acc.push(x);
    }
  }
  cout << acc.pop() << endl;
}

> 5 9 8 + 4 6 * * 7 + * <Enter>
Ctrl+D
> 2075