Cod sursa(job #2188119)

Utilizator ilie0712Botosan Ilie ilie0712 Data 26 martie 2018 22:25:17
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.19 kb
#include <iostream>
#include <fstream>

using namespace std;

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

const int N=100001;
char s[N];
int p=0;
int expresie();
int termen();
int factor();

int main()
{
  in.getline(s,N);
  int p=0;
  out<<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();
        }
        else
        {
            ++p;
            prod/=factor();
        }
    }
    return prod;
}

int factor()
{
    int val=0, semn=1;
    while(s[p]=='-')
    {
        ++p;
        semn=-semn;
    }
    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;
}