Cod sursa(job #814831)

Utilizator bodyionitaIonita Bogdan Constantin bodyionita Data 16 noiembrie 2012 10:26:08
Problema Evaluarea unei expresii Scor 100
Compilator cpp Status done
Runda Arhiva educationala Marime 1.01 kb
#include <cstdio>
using namespace std;
char s[100001],*p;
int eval();
int termen();
int factor();
int main()
{
    freopen("evaluare.in","r",stdin);
    freopen("evaluare.out","w",stdout);
    gets(s);
    p=s;
    printf("%d\n",eval());
}
int eval()
{
    int r=termen();
    while (*p=='+' || *p=='-')
        if (*p=='+')
        {
            p++;
            r+=termen();
        }
        else
        {
            p++;
            r-=termen();
        }
    return r;
}
int termen()
{
    int r=factor();
    while (*p=='*' || *p=='/')
         if (*p=='*')
         {
             p++;
             r*=factor();
         }
         else
         {
             p++;
             r/=factor();
         }
    return r;
}
int factor()
{
    int r=0;
    if (*p=='(')
    {
        p++;
        r=eval();
        p++;
    }
    else while ('0'<=*p && *p<='9')
         {
               r*=10;
               r+=(int)*p-'0';
               p++;
         }
    return r;
}