Cod sursa(job #2501134)

Utilizator rares2004Ioan Rares rares2004 Data 29 noiembrie 2019 09:23:08
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.15 kb
#include <iostream>
#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(s[p] >= '0' && s[p] <= '9')
    {
        val = val * 10 + (s[p] - '0');
        p++;
    }
    return semn*val;
}


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


    return 0;
}