Cod sursa(job #1566497)

Utilizator RaresBadiciBadici Rares RaresBadici Data 12 ianuarie 2016 10:18:28
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.09 kb
#include <iostream>
#include <fstream>
using namespace std;
const int N=100001;
char s[N];
int p;
int expresie();
int termen();
int factor();
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();
        }
        else
        {
            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 in("evaluare.in");
    ofstream out("evaluare.out");
    in.getline(s,N);
    out<<expresie();
    return 0;
}