Cod sursa(job #2612292)

Utilizator PirjolAndreiPirjol-Comanescu Andrei PirjolAndrei Data 8 mai 2020 19:34:55
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.29 kb
#include <iostream>
#include <fstream>
#include <string>

using namespace std;

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

string s;
int p;

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

int main()
{
    in >> s;
    in.close();
    out << expresie();
    out.close();
    return 0;
}