Cod sursa(job #1456126)

Utilizator adina0822Ciubotaru Adina-Maria adina0822 Data 29 iunie 2015 20:43:47
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.18 kb
using namespace std;
#include<fstream>
ifstream f ("evaluare.in");
ofstream g ("evaluare.out");
const long MAX =100010;
char S[MAX], *p=S;

long termen();
long factor();

long eval()
{
    long r=termen();
    while (*p=='+' || *p=='-')
    {
        switch(*p)
        {
            case '+':
               ++p;
               r+=termen();
               break;
            case '-':
               ++p;
               r-=termen();
               break;
        }

    }
    return r;

}

long termen()
{
    long r=factor();
    while(*p=='*' || *p=='/')
    {
        switch (*p)
        {
            case '*':
              ++p;
              r*=factor();
              break;
            case '/':
              ++p;
              r/=factor();
              break;
        }
    }
    return r;
}

long factor ()
{
    long r=0;
    if(*p=='(')
    {
        ++p;
        r=eval();
        ++p;
    }
    else
    {
        while(*p>='0' && *p<='9')
        {
            r=r*10+(*p)-'0';
            ++p;
        }
    }
    return r;
}




int main ()
{
  f.get(S,MAX);
  g<<eval();

  return 0;

}