Cod sursa(job #1098238)

Utilizator eugen_ptrEugen Patru eugen_ptr Data 4 februarie 2014 17:49:47
Problema Evaluarea unei expresii Scor 60
Compilator cpp Status done
Runda Arhiva educationala Marime 1.14 kb
#include <iostream>
#include <cstdio>
#include <cstring>
using namespace std;

char s[20], *p;

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

int main()
{
    freopen("evaluare.in","r",stdin);
    freopen("evaluare.out","w",stdout);
    gets(s);
    p = s;
    printf("%d\n",eval());
    return 0;
}