Cod sursa(job #2376604)

Utilizator IoanaDraganescuIoana Draganescu IoanaDraganescu Data 8 martie 2019 16:40:48
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.12 kb
#include <iostream>
#include <fstream>
#include <cstring>

using namespace std;

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

char s[100005], *p = s;

long termen();
long factor();

long eval()
{
    long r = termen();
    while (*p == '+' || *p == '-')
    {
        if (*p == '+')
        {
            p++;
            r += termen();
        }
        else
        {
            p++;
            r -= termen();
        }
    }
    return r;
}

 long termen()
 {
     long r = factor();
     while (*p == '*' || *p == '/')
     {
         if (*p == '*')
         {
             p++;
             r *= factor();
         }
         else
         {
             p++;
             r /= factor();
         }
     }
     return r;
 }

long factor()
{
    long r = 0;
    if (*p == '(')
    {
        p++;
        r = eval();
        p++;
    }
    else
    {
        while (isdigit(*p))
        {
            r = r * 10 + (*p - '0');
            p++;
        }
    }
    return r;
}

int main()
{
    fin >> s;
    fout << eval() << '\n';
    return 0;
}