Cod sursa(job #2536144)

Utilizator Asgari_ArminArmin Asgari Asgari_Armin Data 1 februarie 2020 16:06:44
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 0.95 kb
#include <fstream>

using namespace std;

ifstream fin( "evaluare.in" );
ofstream fout( "evaluare.out" );

const int N = 100000;
int p;
char s[N + 1];

int expresie();
int termen();
int factor();
int expresie(){
  int sum = termen();
  while( s[p] == '+' || s[p] == '-' ){
    if( s[p] == '+'){
      ++p;
      sum += termen();
    }
    else{
      ++p;
      sum -= termen();
    }
  }
  return sum;
}

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

int factor(){
  int val = 0, semn = 1;
  while( s[p] == '-' ){
    semn = -semn;
    ++p;
  }
  if( s[p] == '(' ){
    ++p;
    val = expresie();
    ++p;
    return semn * val;
  }
  while( s[p] >= '0' && s[p] <= '9')
    val = val * 10 + (s[p++] - '0');
  return semn * val;
}

int main() {
    fin.getline(s, N);
    fout << expresie();
    return 0;
}