Cod sursa(job #1812596)

Utilizator cristianursacheCristian Ursache cristianursache Data 22 noiembrie 2016 11:08:09
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.1 kb
#include <fstream>

using namespace std;

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

const int N = 100001;
char s[N];
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(isdigit(s[p]))
    {
        val = val*10 + (s[p] - '0');
        p++;
    }
    return semn*val;
}

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