Cod sursa(job #2189434)

Utilizator AlexandruabcdeDobleaga Alexandru Alexandruabcde Data 28 martie 2018 12:15:55
Problema Evaluarea unei expresii Scor 10
Compilator cpp Status done
Runda Arhiva educationala Marime 1.13 kb
#include <fstream>

using namespace std;
ifstream f ("evaluare.in");
ofstream g ("evaluare.out");
char s[100005], *p;
int eval();
int termen();
int factor();
int eval ()
{
    int r;
    r = termen();

    while (*p == '+' || *p == '-')
    {
        if (*p == '+')
        {
            p++;
            r += termen();
        }
        else if (*p == '-')
        {
            p++;
            r += termen();
        }
    }
    return r;
}

int termen ()
{
    int r;
    r = factor();
    while (*p == '*' || *p == '/')
    {
        if (*p == '*')
        {
            p++;
            r *= factor();
        }
        else if (*p == '/')
        {
            p++;
            r /= factor();
        }
    }

    return r;
}

int factor ()
{
    int r = 0;
    if (*p == '(')
    {
        p++;
        r = eval();
        p++;
    }
    else
    {
        while (*p >= '0' && *p <= '9')
        {
            r = r*10 + (int)*p - '0';
            p++;
        }
    }
    return r;
}
int main()
{
    f.getline(s,100002);
    p = s;
    g << eval() << '\n';

    return 0;
}