Cod sursa(job #1832718)

Utilizator vladboss2323Ciorica Vlad vladboss2323 Data 20 decembrie 2016 19:46:22
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.38 kb
#include <iostream>
#include <fstream>
using namespace std;
/*
(1+1)*13+10/2
expresia = suma de termeni
termen = produs de factori
factor = constanta sau expresie
*/

const int N = 100001;

char s[N];
int p=0;

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

int main()
{
    ifstream in("evaluare.in");
    ofstream out("evaluare.out");
    in>>s;
    out<<expresie();
    return 0;
}