Cod sursa(job #1830083)

Utilizator leraValeria lera Data 16 decembrie 2016 09:26:17
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.09 kb
#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("evaluare.in");
ofstream fout("evaluare.out");
string s;
int i;
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
        {
             i++;
             r-=termen();
        }
    }
    return r;
}
long long termen()
{
    long long r=factor();
    while(s[i]=='*' || s[i]=='/')
    {
        if(s[i]=='*')
        {
            i++;
            r*=factor();
        }
        else
        {
            i++;
            r/=factor();
        }
    }
    return r;
}
long long factor()
{
    long long x=0;
    if(isdigit(s[i]))
    {
        while(isdigit(s[i]))
        {
            x=x*10+(s[i]-'0');
            i++;
        }
    }
    else if(s[i]=='(')
    {
        i++;
        x=eval();
        i++;
    }
    return x;
}
int main()
{
    getline(fin,s);
    fout<<eval();
    return 0;
}