Cod sursa(job #2676686)

Utilizator Queen10Andrada Georgescu Queen10 Data 24 noiembrie 2020 19:18:11
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.31 kb
#include <fstream>

using namespace std;

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

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

int expresie ();
int termen ();
int factor ();

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

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

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

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