Cod sursa(job #2677685)

Utilizator Sunt_3l3vTaut Radu Alexandru Sunt_3l3v Data 27 noiembrie 2020 10:39:07
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.25 kb
#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

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 val = 0, semn = 1;
    while(s[p] == '-')
    {
        p++;
        semn = -semn;
    }
    if(s[p] == '(')
    {
        p++;
        val = expresie();
        p++;
        return semn * val;
    }
    while( '0' <= s[p] && 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();
}