Cod sursa(job #2926203)

Utilizator radustefanescu2006@gmail.comRadu Stefanescu [email protected] Data 17 octombrie 2022 10:46:44
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.19 kb
#include <iostream>
#include <fstream>

using namespace std;

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

char s[100001];
int i;

int expresie();
int termen();
int factor();
int constanta();

int main()
{
    fin >> s;
    i = 0;
    fout << expresie();
}

int expresie()
{
    int r = termen();
    while(s[i] == '+' || s[i] == '-')
    {
        if(s[i] == '+')
        {
            i++;
            r += termen();
        }

        else
        {
            i++;
            r -= termen();
        }
    }
    return r;
}

int termen()
{
    int r = factor();
    while(s[i] == '*' || s[i] == '/')
    {
        if(s[i] == '*')
        {
            i++;
            r *= factor();
        }
        else
        {
            i++;
            r /= factor();
        }
    }
    return r;
}

int factor()
{
    int r;
    if(s[i] == '(')
    {
        i++;
        r = expresie();
        i++;
    }
    else
    {
        r = constanta();
    }
    return r;
}

int constanta()
{
    int r = 0;
    while(s[i] >= '0' && s[i] <= '9')
    {
        r = r * 10 + s[i] - '0';
        i++;
    }
    return r;
}