Cod sursa(job #2575502)

Utilizator FrostfireMagirescu Tudor Frostfire Data 6 martie 2020 13:54:47
Problema Evaluarea unei expresii Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.18 kb
#include <iostream>
#include <fstream>

using namespace std;

ifstream f("evaluare.in");
ofstream g("evaluare.out");

int i;
string s;

int eval();
int termen();
int factor();

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

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

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

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