Cod sursa(job #1360958)

Utilizator zpaePopescu Andreea zpae Data 25 februarie 2015 18:57:44
Problema Evaluarea unei expresii Scor 40
Compilator cpp Status done
Runda Arhiva educationala Marime 1.11 kb
#include <fstream>
using namespace std;
const int N=100000;

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

char s[N+1], i=0;

long long termen();
long long factor();

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

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

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

int main()
{
    in>>s;
    out<<eval()<<endl;
    return 0;
}