Cod sursa(job #2676694)

Utilizator DanSucuDan Sucu DanSucu Data 24 noiembrie 2020 19:28:20
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.23 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();
        }
        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 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()
{
    in >> s;
    out << expresie();
    return 0;
}