Cod sursa(job #758372)

Utilizator classic_gamesofia nitoi classic_game Data 15 iunie 2012 15:04:58
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.21 kb
#include <iostream>
#include <fstream>

using namespace std;

int p;
char s[100001];

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

int expresie ()
{
    int sum=termen ();
    while (s[p]=='+' || s[p]=='-')
    {
        if (s[p]=='+')
        {
            p++;
            sum+=termen();
        }
        else
        {
            p++;
            sum-=termen();
        }
    }
    return sum;
}
int termen(){
    int prod=factor();
    while (s[p]=='*' || s[p]=='/')
    {
        if (s[p]=='*')
        {
            p++;
            prod*=factor();
        }
        if (s[p]=='/')
        {
            p++;
            prod/=factor();
        }
    }
    return prod;
}

int factor (){
    int val=0, semn=1;
    while (s[p]=='-')
    {
        semn=-semn;
        p++;
    }
    if (s[p]=='('){
        p++;
        val=expresie();
        p++;
        return semn*val;
    }
    while (s[p]>='0' && s[p]<='9'){
        val=val*10+s[p]-'0';
        p++;
    }
    return semn*val;
}

int main()
{
        ifstream f("evaluare.in");
        ofstream g("evaluare.out");
        f.getline(s,100001);
        g<<expresie()<<"\n";
        return 0;
}