Cod sursa(job #255878)

Utilizator DraStiKDragos Oprica DraStiK Data 10 februarie 2009 20:27:46
Problema Evaluarea unei expresii Scor 60
Compilator cpp Status done
Runda Arhiva educationala Marime 1.06 kb
#include <stdio.h>
#define DIM 100005
char a[DIM],*p=a;
int eval ();
int termen ();
int factor ();
int main ()
{
    freopen ("evaluare.in","r",stdin);
    freopen ("evaluare.out","w",stdout);    
    fgets (a,DIM,stdin);
    printf ("%d",eval ());
    return 0;
}
int eval ()
{
    int r;
    r=termen ();
    while (*p=='+' || *p=='-')
    {
        if (*p=='+')
        {
            ++p;
            r+=termen ();
        }
        else
        {
            ++p;
            r-=termen ();
        }
    }
    return r;
}
int termen ()
{
    int r;
    r=factor ();
    while (*p=='*' || *p=='/')
    {
        if (*p=='*')
        {
            ++p;
            r*=termen ();
        }
        else
        {
            ++p;
            r/=termen ();
        }
    }
    return r;
}
int factor ()
{
    int r=0;
    if (*p=='(')
    {
        ++p;
        r=eval ();
        ++p;
    }
    else
        while (*p>='0' && *p<='9')
        {
            r=r*10+*p-'0';
            ++p;
        }
    return r;
}