Cod sursa(job #1778636)

Utilizator elffikkVasile Ermicioi elffikk Data 13 octombrie 2016 22:40:26
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.12 kb
#include <iostream>
#include <fstream>
#include <string>
#include <cstdlib>
using namespace std;

long operatie(long x, long y, char c) {
    if (c == '+') {
        return x+y;
    }
    if (c == '-') {
        return x-y;
    }
    if (c == '*') {
        return x*y;
    }
    return x/y;
}

bool contains(string s, char c) {
    return s.find(c) != string::npos;
}

long eval(string::iterator a, string::iterator b) {
    string op[2] = {"+-", "*/"};
    for (int j = 0; j < 2; j++) {
        int p = 0;
        for (string::iterator i = b-1; i >= a; i--) {
            if (*i == '(') {
                p++;
            } else if (*i == ')') {
                p--;
            }
            else if (p==0 && contains(op[j], *i)) {
                return operatie(eval(a, i), eval(i+1, b), *i);
            }
        }
    }
    if (*a == '(') {
        return eval(a+1, b-1);
    }
    return atoi(string(a, b).c_str());
}

int main() {
    ifstream fin("evaluare.in");
    ofstream fout("evaluare.out");
    string s;
    getline(fin, s);
    fout<<eval(s.begin(), s.end());
    return 0;
}