Cod sursa(job #2735495)

Utilizator avtobusAvtobus avtobus Data 2 aprilie 2021 14:43:17
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.27 kb
#include <stdio.h>
#include <bits/stdc++.h>

#define rep(i, n) for(int i = 0; i < (int)(n); i++)

using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;

ifstream fin {"evaluare.in"};
ofstream fout {"evaluare.out"};

string s;

int eval(int &pos);
int termen(int &pos);
int factor(int &pos);

int eval(int &pos) {
  int res = termen(pos);
  while(s[pos] == '+' || s[pos] == '-') {
    if (s[pos] == '+') {
      pos++;
      res += termen(pos);
    } else {
      pos++;
      res -= termen(pos);
    }
  }
  return res;
}

int termen(int &pos) {
  int res = factor(pos);
  while(s[pos] == '*' || s[pos] == '/') {
    if (s[pos] == '*') {
      pos++;
      res *= factor(pos);
    } else {
      pos++;
      res /= factor(pos);
    }
  }
  return res;
}

int factor(int &pos) {
  int res = 0;
  if ('0' <= s[pos] && s[pos] <= '9') {
    while('0' <= s[pos] && s[pos] <= '9') {
      res = res * 10 + s[pos] - '0';
      pos++;
    }
    return res;
  } else if (s[pos] == '(') {
    pos++;
    res = eval(pos);
    pos++;
  }
  return res;
}

int main(void) {
  // freopen("evaluare.in", "r", stdin);
  std::ios_base::sync_with_stdio(false);
  std::cin.tie(NULL);

  fin >> s;
  int pos = 0;
  int res  = eval(pos);
  fout << res << '\n';

  return 0;
}